Because of the negative side effects… Sure gato COULD block them but isn’t guaranteed on defence…
Plus there are other options who can do the buff-boosting just as well in terms of the total # of buffs, or more, (e.g. costume belith or any other hero who does +2 buffs to all allies) who DON’T have the negative side-effect.
Defence I don’t need that kind of thing. My defences still get A grade. The one time I DID tank him with gato flanks it ended up with a D grade so… no bono there.
In Offence I have tried using him and just get annoyed… Having tho hold back his stuff so I can have Gato Ready to go just annoys me. Or relying on “refiring” specials is just an unnecessary gamble. Then in terms of his “buffs” I refer to above where there are other heroes who don’t have the negative effect & still have the same number of buffs or better synergies without the negative effects.
Shrubbear I have said many times is a better flank than a Tank but has the versatility to do both. By-Ulf doesn’t. Plus he has no draw-backs, unlike By-Ulf.
Grevle does a full team attack boost AND health boost. Pair him with another healer and you can easily negate any incoming damage you would be recieving & build up a buffer. Plus affects the entire team & has no negative side effects… Unlike By-Ulf.
TLDR is that I dislike the “negative” effect & can do as well or better without him. I levelled By-Ulf and had high initial hopes for him (like you still do) but now never use him. Ever.