For low-income users who don't already own a desktop, I think it can make quite good sense. A "good" keyboard/mouse/monitor/etc. are not strictly necessary, and if you can't afford new ones, used ones can be had for extremely cheap or even free often times, like from garage sales, thrift shops, friends etc. And most of those people have a phone already, so adding the peripherals is not a big cost for them, but a full size desktop likely would be.

I can get a working LCD screen, keyboard and mouse from my local thrift shop for $20, whereas the cheapest new laptop is at least $200.