Are they? I've never not used healers so I guess I wouldn't know. Would I be doing better or having more fun if I was using something else? I guess that never occurred to me.
It's personal preference.
One problem with healers was that they had excess recovery for a long time.
Nowadays though, hp boosts makes recovery more important than ever.
My I&I team wouldn't be able to support its 30k hp if not for the average 600 recover per member.
As you roll better members and take away your sirens/echidnas in your healer teams, your hp stops being pathetic and rcv starts being worthwhile.
As for "more fun or not" that's also personal preference, I find being able to take 10k per turn and recover that back as fun, some might enjoy just OHKO whatever every turn.
About stat being bad, recovery is weird because it doesn't as directly affects you as hp and attack does. Whenever new stuff comes out with 0 recover I see comments about *LOL 0 RCV again this guy is bad* too, so can you say recovery is useless? definitely not. But how much recovery is enough? There definitely a point where you have excess and more rcv is just wasted potential. If you believe in the 10hp=5atk=3rcv like I do, healers have stat just as good as any other typings. Otherwise you'd see them as hilariously mediocre. (The typical LMeta team before the HP boost does have too little hp to take advantage of the recovery. Light Healers have much better statsticks to put in their team nowadays though, e.g. DQXQ, theLightKnight)