That small orange translucent plastic protective strip comes with the screw terminals. Some screws terminals will have them, others won't. They're not a full solution, but they do make things a little bit safer.
Those 3d printed ones you link to are what I was thinking. Sadly most 3d printer filament is not firesafe (not self extinguishing) and start to soften at around 60degC (can collapse and cause shorts/fires). For one-offs that you keep an eye on they're fine, but if you're making this for someone else then I'd try to do something better.
> Besides lower cost, how is this type of Mean Well power supplies compared with lab bench power supplies used in schools?
N.B. MeanWell is just one (popular) brand. There are cheaper and more expensive options for these perforated chassis screw-terminal power supplies. I don't know if there is a better or more common term to describe them.
An adjustable lab bench power supply can work, but there are a few potential gotchas.
A power supply that only needs to supply one voltage will be better optimised (cheaper, smaller, simpler, longer life, higher power efficiency). The transformer only needs two windings and their ratio can be more optimal, it doesn't need relays to switch transformer taps, there are less parts to fail, transient responses can be better tuned, etc. Or in English: the more specialised you are the better you can do that one job, the more generalised you are the less well you can do any particular job (but you can do them all).
Many bench lab power supplies are fully isolated (that's why on the front panel the earth banana jack is separate to the negative banana jack). The perforated chassis screw-terminal style power supplies are not isolated, output ground is mains ground. You probably don't care for your application.
A lab bench power supply will have both constant-voltage and constant-current feedback control. A perforated chassis screw-terminal one instead only controls a constant-voltage; if your load draws too much current then it will switch off completely (Over-Current-Protection or OCP) instead of gradually reducing output. (An exception are some LED power supplies in the same metal box form factor, but that's another story).
Knobs on lab bench power supplies can be banged, knocked or their pots can fail over time (potentially then sending way too high of a voltage into your devices). Also if they use encoders instead of pots then they must store and remember the settings between power cycles, which sometimes they fail to do. You don't want to turn your stuff back on and find out the power supply only wants to output 1V at 1A (or requires pressing an "enable" button manually).
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