I'm not calling it harmful -- merely an utter waste.
Using XIV "combos" is to purposely make a single action take up multiple buttons of space. And that has accordant, if minor, issues:
Assuming a 3-step combo, we either...
- lose 2 actions (each 1 button) to support that 3-button single action just to keep that slightly less punishing an option,
--or--
- we effectively make the already zero-advantage option of non-consolidation (especially, without a context in which those tactile cues of moving from 1 to 2 to 3 would be useful, as on ShB or EW SAM, HW NIN, etc.) also waste handier button-space that's becoming increasingly more valuable/limited.
XIV "combos" are pure bloat. If you want to use them to offer multiple different attack animations and some ppgcd cycling on a single action/button, by all means, go for it. But there's no point in constraining the rest of the kit around a
pretense that those are separate actions.
At which point, you'll have just another Healer with
n non-healing GCDs, but one of said GCDs has 3 animations. It's an incredibly small improvement, if any. And you could as easily have provided that animation variance instead through
actual skill interactions (procs, status effect conditionals, branching sequence-based conditionals instead of merely a single rigid series of unlocks, etc.).
Any other way to use multiple actions together (or, better put, having each skill actually be its own action) would be better, be they actual combos (see other MMOs) or whatever other means of interaction. So while I wouldn't be opposed to a consolidated combo, we can most certainly do better.