Used to be. In 5th, all you lose is the possibility to switch spells. And with a focus no need for most components except the ones that have a gold cost.
ONLY if the player is cool with it. I prefer to break immersion that lose a player. If I have to choose, fuck immersion, I love my players and I want to keep them at my table.
Althought I do love immersion. You can have your cake and eat it too. Just… fuck it if the cost is a player’s fun.