RE – Dispelling:
Mnesseus is allowed in any tournament that Belith is allowed. Tyrum is guaranteed allowed in the ones Belith isn’t.
Personally, I find those heroes to be much better for dispelling buffs than Belith. I don’t dislike Belith, but I just think it’s better to have a fast dispel (particularly so in Buff Booster).
Direct healing vs HoT
3*s don’t have much HP. 800ish average with troops involved, meaning Belith’s 32% direct heal usually is about 256 HP recovered immediately.
Compare that to the 459 HP you recover eventually after 3 turns.
The same turn you use Belith’s skill, you recover 152 HP immediately. 100ish points more of direct healing, I really don’t see any cases where that would be more useful than higher overall healing
Personally, I think cBelith is always better to have over regular Belith.