To add a bit of perspective, from someone who sells classic video games for a living: this console's main point isn't to be affordable or play high-end games. Its target market probably already owns an OLED Switch, a Vita, PSP, every DS model and 2 or 3 Game Boys (one of which is modded with an IPS display).
It's designed to be interesting. That's it. Doesn't need to have a killer app or broad library.
Any utility it offers comes from the fact that it's something to add a bit of spice and fun to an already broad games collection, and possibly the clout that comes from showing other people that you own one.
From that perspective, I think these guys have absolutely hit it out of the park. Not surprised by the success of this at all.