Because imo... that is the answer. We have seen so many stupid closed ecosystems of home automation stuff come and go, I dunno why you'd mess with anything else at this point. In fact I just got another email reminder that Google is turning off the old Works with Nest stack. Remember Nest? Yeah...
I think the issue is more the attitude towards security and system stability that is implied by such installation methods, which is apaprently endemic to the entire "JS ecosystem". That attitude being "who cares about security or stability?"
When It's my system and I don't want to mess with it, just set stuff up and have it run trouble free and do the things I want (and only I want), then I do care about such things and agree that JS has no place other than sacrificial toy boxes that get insulated from "real" computing like they was a modem with its phone number posted at the payphones by the 2600 meetup.