I was wondering, when using familiars whose both levels are on max, you get anything when you engage in battles or not as they are on max? If this is the case do you still use familiars Who are on maximum stats? Thanks.
When your familiar's level is full, it does not gain any further exp in either its attributes (str, def, etc) nor its ability points.
You gain nothing more other than the fact that it'll be more likely for you to win battles using a fully levelled familiar.
In story mode, it's a good idea to select your most powerful familiars as main with a less levelled familiar in reserves. Go through the map using the reserves as their hp re-fill every time they level up, which might save you some balms in case you need them in the future.
I hope that answered your question