>>25966195D Mark III does not have IBIS. The only Fool Frame camera that does is the Sony A7II, and its IBIS is not nearly as good as Olympus'. In addition, its lenses are absolutely massive, nearly deleting the size advantage against a DSLR. In addition to that, the native lens selection is weak, and adapted lenses are even larger yet.
>>2596618Not everyone brings a studio with them when they go on photo walks in low light. Not everyone wants to lug around a tripod either. Even an ultralight carbon tripod is a pain in the ass to carry around. You went mirrorless to reduce the amount of stuff you carry around, after all. Not all angles happen to have a convenient shelf, rail, fence post, etc to lean on.
Also, only some Canon zoom lenses and slow primes have IS. And they won't give you five stops worth.