Career timing and post military opportunities. In the Navy, if you don’t screen for squadron command the odds of flying post department head (ADO) are almost zero.
For me personally, I’m a senior O-4 that flew helos in the Navy and I was looking at a non-flying desk job for at least three years. With no guarantees of flying afterwards (even though I volunteered for UPT instructor, etc), and the Air Force offering me the chance to fly heavies for at least the next four years, it was a no brainer. Even if I don’t fly till I retire I’ll have a lot better shot at the majors afterwards instead of slogging through the regionals for 5-6 years waiting on flow through.
The same applies to a lot of the guys I know that have swapped over. No real aspiration for command but happy to fly our asses off for the rest of our careers. That, and the 75 day tanker deployments are quite ok when compared to 6-9 month boat deployments.