I gave a little thought to these myself, as I saw one for $80 that had 5x magnification... and since it doesnt have to hold a zero, or even have a reticle...
But then reality set in:
- quality of the image, due to cheap optics... may be simply penny wise pound foolish. Meaning $80 wasted.
- will it fog up badly the first time the weather is less than mild? Rain? Cold weather? Cool morning hot afternoon?
Look, if someone wants to "play" or just use it only for plinking, well, why not, have at it and save a few bucks.
But... the thing about firearms is that even if you never plan to use it for anything but paper targets on nice days, the real world, and Murphy's Law has a way of sneaking up on the poorly prepared. I've seen that often enough, you all probably have seen examples of that too.
A few years ago I read a newspaper article from BC, i think it was posted on this site. a neighbour saw a mountain lion stalking a young girl... and the neighbour had to scramble to get a rifle ready and then take the most critical shot of his (her?) life. Doing so would be difficult. Doing so with poor gear that only barely works as a toy, like a magnifier that fogs up when you REALLY need it to work... could make that impossible.
We civilian gun owners don't tolerate unreliable guns. Nor do we tolerate unreliable red dots, iron sights too fragile, or optics that can't hold a zero or fog up.
Now... all that said... the real proof is in the testing. Would you be willing to test?