Title says it all.
Seems to me like heating and leveling your weapons is a result that shows you use that weapon enough for it to become stronger.
However, why isn't it possible to heat a weapon in LD while you're using the same weapon as well? Doesn't even have to be a lot, like 5 matches for lvl 2 on a 5* weapon, 6 matches for lvl 3 etc etc.
It would certainly make heating way less of a pain and the game overall more enjoyable to me if this were possible.