Sure, fountain pens are a bit fiddlier than your average ballpoint. But they do have their advantages.
- The colors you can write in is not a direct function of the manufacturer of the pen. Like the look of one pen and the ink colors offered by someone else? You can do that.
- More ink colors. For those of us with acute color discrimination, this can be really useful.
- Washable ink. For those unhappy accidents. Sure, some ink colors do stain.
- …which brings me to: waterproof and forgery-proof inks. Sure, there are ballpoints (Uniball Signo) that do that as well, but not in as many colors as are currently available for fountain pens. Note that these are not washable from clothing, so you can go to both extremes. Here are some torture test results.
I’ve seen fountain pens from $1 all the way up to “Oh my God!” levels, where that was seven figure to the left of the decimal point. Most expensive I’ve held in my hands was five figures. All of them can use the same inks.