Where "users with slow devices" equals "anyone trying to keep hardware running more than a few years", it seems. It's enforced obsolescence.

I've said for a long time, devs should be forced to take a survey of their users' hardware, and then themselves use the slowest common system, say, the 5th-percentile, one day a week. If they don't care about efficiency now, maybe they will when it's sufficiently painful.