Yeah. The NES/SNES/PS Classic sell because you can't (legally) play those games without trying to acquire one of those old consoles and games. Which for some games and consoles can be difficult, or require a bit of work (e.g. console doesn't work and needs repair). These work because you pick it up, hook it to your TV and you're playing in 5 minutes.
The PC classic I don't understand - most of the games already can be played on any decent modern PC, and places like GOG make it super easy to play (install and run). You're not gaining much since today's hardware can run yesterday's games, be it natively on Windows already, or through something like DOSBox. You don't have to go out and buy a retro PC to play them (you could, but it's optional), so I really don't see the point. Plus, the control schemes - joypad, keyboard, mouse, etc?
The point is that NES/SNES/PS Classic work because finding hardware and the games are harder. The PC Classic doesn't because well, the games can still run.
Even the C64 Mini has potential because it's not as easy to find working Commodore 64s these days (the vast majority were probably put in an attic decades ago and have aged poorly, requiring restoration work).