It has a lot going for it - but, yes, it takes time! However, that only adds an element of excitement if you're up to it and reasonably literate. Any roleplays l've done using Chat Gram have always felt horribly rushed and leaving little to savour, certainly not the suspense and tingle of anticipation that waiting for the next 'instalment' brings!
In rolepaying by correspondence you can combine happy memories with added refinements (including verbal descriptions of surroundings, procedures, unspoken thoughts of doctor and patient, reactions by the patient, much else!) ...
Erotics should not be all, or even largely, genital-focussed. (Well, that's my view!) Roleplay by correspondence can give an added 'dimension' and be deeply satisfying.
- Ken