Agreed in terms of live memory, but if it's purely measuring heap size then it makes more sense. So it possibly could run with a much stricter memory limit, but

Agreed in terms of live memory, but if it's purely measuring heap size then it makes more sense. So it possibly could run with a much stricter memory limit, but with the tradeoff of more GC (and for a compacting GC, this would mean lower throughout, since the GC time is proportional only to live objects. May as well let the garbage pile up as much as you can and therefore do fewer collections)