that question aside ... upgrading an inexpensive Chinese built, if not designed, piece of test equipment for something better raises the question to exactly where the value of the product is? 
I mean -- not saying it's
good value, but if the value to one is more about developing skills and gaining knowledge, poking around such a unit is an affordable way to do so, while having something that is at least nominally usable at the outset.
Or, think of it as building your own, with fewer steps: the circuit's already designed, you have all the parts necessary right there, it might not be well conceived or put together, but it's most of what you need, there's no enclosure crafting, the displays and buttons are definitely usable, the power stage and controls might even be usable with tweaks; of course one needs to determine how much work is required to get it to a more confident and reliable state.
Or, if you're in a part of the world where good stuff just doesn't exist, it's not imported, there aren't normal sales channels, ordering direct from China isn't simply the convenient drop-ship we have here in the US, or the west in general; it can be a huge PITA to get something even workable, and then to improve it to a reliable state, while spending much less -- and much cheaper -- labor to get there, can be a win. Particularly for the beginner or hobbyist where labor may be marked down or written off entirely, and, again, learning opportunities.
Whereas if you go the "normal" route of designing (or "shopping" schematics online... blarf!) your own lab PSU, and it's a whole bunch of work just to get anything together at all (transformer, enclosure, controller, power stage, heatsinks, terminals, panel meters..!), and in the mean time you can't work on other more interesting projects without a lab supply handy -- if one has more interest in the latter -- and you can always go back and fix up this unit -- well, that might serve better.
So yeah, maybe not great reasons, but I don't doubt out-of-hand that there is legitimate value to be had in such a unit. It's not something I'll be buying any time soon (even if I didn't have supplies already), but also not something I'll begrudge someone from considering. Especially on a meager budget.
Anyway, there's a very real market like this, albeit moreso on the mechanical side of things -- you see trashy iron castings with crap millwork all the time in, like, hobby machine shop level tools -- drill press, vice, X-Y tables, entry-level lathe/mill/combo, bandsaw, etc. The nature of the market is, if the manufacturer spent
any more time on any step of production at all, they would price themselves out of the market -- it's a race to the bottom, remember -- and the low price range always and forever will and must be -- so, that they can offer, frankly anything even resembling the product in question, at all, is remarkable, and given that cost pressure, they can do some pretty good quality despite it. No, not "quality" in the usual sense of something that's functional, consistent and reliable out of the box -- but something one can get good use out of, give or take reasonable effort put into it, and despite its many shortcomings. The best explanation of this I've seen is here:
Now, it's not quite the same for electronics, because -- well, give or take your welding capability, and how suitable your substrate materials are and etc. (good luck welding on those cracker-barrel gray iron castings..!), but, with mechanics, you can potentially do quite a lot in terms of repair, re-tread, grind, fit and finish, paint and polish, etc., like the above; the same need not be true of electronics, where MCUs might be locked, or in any case source-unavailable, let alone whatever dev tools would be needed for the no-name chips used, and major geometric errors like creepage and clearance fundamentally affect the safety and reliability of the product in a way that isn't feasible to fix, short of remaking the entire PCB. So, there is a significantly smaller chance that equipment like this can be improved, say to good western engineering standards, given reasonable effort. That's unfortunately the nature of something as high-level as electronics; even if the house is good, you can hardly fix the foundation without rebuilding the house atop it. But still, much of the stuff needed is present, and, if one wanted to make repro boards maybe, with open firmware, and all the right precautions, and, filtering and protection and all that, you could; and doing so would benefit every other user -- if not immediately or directly, then by bits and pieces here and there, overall.
Long story short, if one is interested in (or not discouraged by) doing some fix-ups to their tools, there exist...whole markets for that, basically; I wouldn't begrudge anyone for opting to do so, whether by preference, financial limitations, or other extenuating causes like geopolitics entirely. Just beware the many ways such a product can fail, and how to familiarize oneself with their working, so as to be able to fix it.
Tim
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