I agree, it's whatever you prefer. Apps are good for what they're specialised in, but problems do exist and probably some of the reason so many companies provide parallel features already present in other software. Working in between apps can pose problems like, syncing changes between designs, interruption to creative flow, difficulties collaborating across teams.

Another part of it will be acquisition, for customers that don't have certain software they can provide feature parody allowing them to attract more customers.