There’s multiple logs posted in this very thread of healers spending 30% of their gcds on damage buttons and it causing absolutely zero problems for the group.
There are bosses that do nothing to anyone but the tank outside of specific mechanics. There are trash packs that only deal damage to players if they get casts off. Both are very common situations where the healer has large swathes of time with literally nothing to heal.
Hall of atonement has overall pretty engaging trash for healers but the bosses? 3/4 of them do nothing but tickle the tank outside of very specific moments.
Who are you healing on Halkias if everyone is placing debris and avoiding the beams?
Who are you healing on Aleez when there’s no active ghosts and you’re handling dispels fine?
Who are you healing on chamberlain outside of his two intermissions as long as nobody’s getting hit by a statue?