Drum fills are fun to play. At home, I say knock yourself out. On the bandstand they can be reason you get fired.
When the music presents a space for a drum fill, it also presents a space for the pianists, guitarist, bassists, various horn players, and hand percussionists to add their own noodly bits too. A real "Hey look at me moment". Sunday morning worship bands are famous for this. The results are cacophony and distraction.
Singers hate this because naturally they want to be the centre of attention. The listener gets confused. Who do I listen too? If you aren't the band leader, band leaders really hate this too, it often breaks up the flow.
Try this experiment:
Listen to fifty tunes in various genres, make a note of how "filly" they are. Now that being said there is music that is crazy busy, loud, fast, and fun. Knock yourself out. But for the gigging musician/drummer plan your moves carefully.
If I can help you out, call me.
David Story, drummer, pianist, qualified online music teacher