There's zero inconvenience barrier between my fountain pen with ink cartridges and my rollerball pen with ink refills. Writing and replacing the ink cartridges are functionally equivalent between the two. But my fountain pen has a 1mm stub nib that gives the lines some distinct width, so I use it when I want that characteristic.

A combination of a good fountain pen that matches your own writing (price doesn't matter) and good quality paper is an asset to me, not a handicap. The ink flows, the hand to pen to paper feeling/feedback/sound brings out words and sentences that typing doesn't.

I like FPs because they are the easiest on my wrist, they don’t go to the landfill as often, and I like to use different colors (have a bunch of inks and have even mixed them myself to achieve the “perfect” aquamarine). Also, the physical principles on which they operate are curious.