I remember there was a time years back when there were "light" variants of apps, usually intended for underpowered or older Android phones, but that also came in handy if you were in a situation where you had shitty cell service, or if you needed to preserve your battery. You could run the Opera Mini browser on a trash phone and it was blazing fast without wrecking your battery. Maybe 5% of sites would have a rendering issue, but you could always switch back to your main browser if you needed to use it.

Nowadays, I think the trend is more toward putting a battery-saver or data-saver mode inside an existing app, rather than creating an entirely new app, and I don't see any reason why Apple couldn't do something like this in Safari if they wanted to.