From a security standpoint, it would be better if no apps could be installed at all. I've hidden the store on my grandma's device before because she was quite likely to just tap anything, shiny or no.
(Every time I'd visit, she'd have managed to turn the carefully laid out homescreen to "simple mode" and she couldn't find half her apps because they were now either on the second screen or off the homescreen altogether. The only logical way to change this setting is long press on an empty area, look around, and press the button with the "simple" keyword. I suppose her thought process was: simple? That sounds good for me! And then not connecting this action to that her OS now looks completely different and just trying to keep using it as if everything is normal.)
But security doesn't come in absolutes and this should absolutely not be enforced as a general policy for everyone. It feels like limiting where people can drive because some roads are more dangerous than others (some have trees, others have distracting ads, imagine we'd let just anyone go anywhere!), and the road owner can legally decide where you can go because all destinations you could possibly want are are on someone else's road (where someone else is a single entity)