I've got a frame pump on my gravel bike, because:
- I already had the pump (a Silca) from a vintage touring bike.
- The pump has a gen-u-ine Campagnolo metal pump head that will probably outlast the bike. (It outlasted the last bike it was on.)
- Weight isn't particularly important on that bike.
- The pump is a perfect fit for the frame, so why not use it?
Other than that, I wouldn't buy a new frame pump today.
My Dahon folder has a Postpump, built into the seatpost.