Personally, I don't mind digital fonts in comics, but...
It's very easy to let the default text settings slip into your work. If you don't adjust things it'll look "basic" or "amateur". Make sure everything about the text is intentional and improves whatever style or mood you're aiming for. Check the vertical line spacing, the distance between letters (wide or narrow), and make sure whatever font you use has all the characters you might need. I once found one I loved, but it didn't have quotes or most punctuation marks. WTF?!
From a graphic design point of view, fonts are like language accents, which is what I believe you're going for. Finally, if your font is hard to read either use it very sparingly or find a replacement. Script/cursive fonts are the worst. Your readers will thank you.
I also use a different font for a ghost character in my comic, but he also gets a special spooky speech balloon style to go with it. I even had to switch out his font once his dialog got longer because it wasn't easy to read.