Can they cycle through some states and guess what sort of device is attached? yes. Can they cycle some states and check pass/fail against a specific pattern? yes. But thats about it.
Right, so imagine I have a box full of used 74-series logic chips to repair old arcade machines.
I pull out one that identifies as a "7400 Quad 2‑input NAND Gate" and it says "74LS00" on the back then there's a good chance it's a working chip. If it doesn't identify the chip then it gets binned and I look for another one.
ie. This device is doing
some level of "testing", not just identifying chips, hence then word "tester" printed on the front of it.
Is it guaranteeing the outer limits of the datasheet specifications? No of course not, but I don't think there's any gadget for that. These are cheap, they're fast, they can save a lot of wasted time, they're
testers.
(And OP can be confident they're
not a scam or complete waste of money, which is what he was asking).