With good technique, you should be able to do both. BUT have you heard a voice holding out a note but beneath it all, it just wants to flutter? Have you heard a voice do runs but gets slower the longer the run is?
Anyway, that's it! Most of us have one or the other. Use your natural strength to make some sort of mark for yourself!
Flutter voices tend to be smaller in nature, and holding voices tend to be bigger.Since I do sing opera, let's relate it to fach Smaller flutters are coloratura/leggiero. Bigger flutters are like the full lyric coloratura. Smaller holds can be the light lyrics. Bigger holds can go into the dramatics.
Know yourself! Grow yourself!