That's kind of it, yeah. She is probably deciding not to go nude not because she has qualms with it but because she thinks it's more profitable this way. If you look at some of the most popular e-girls they follow a similar pattern. Peachjars does nips (like Mikomi has), Amouranth is infamous for her scams, Nigri doesn't do nudes either. The moment you've been fully naked the magic is gone, there's no more incentive for whales to get sets with the "well MAYBE this one is the one where she finally shows more", we saw something similar with Delphine.
I don't think it's because she is pretentious about what she does. Mikomi strikes me as one of the most money-focused ones, if it was about justifying to herself she'd do more pretentious stuff like talking about how she's an artist, being on cosplay panels, she would complain about how people don't take it seriously rather than about how much she has to pay in taxes
. She knows she's selling porn, she just does it the way she thinks it's the most profitable for her, and it's clearly working since she's making money hand over fist.
Her current model is selling you a nude set with pasties and trying to get you to believe that it's not another nude set with pasties. For her next birthday she'll maybe show some nip in a roundabout way and that will be it.