Tabletop Gaming

It can be fun if done sparingly, for a few colorful recurring characters. But I've seen GMs do it systematically at RPG conventions, and I find it awkward.

What I find important is not making voices, it's interpreting the NPCs to give clues about their personality, their education, their state of mind and so forth.

As a player, I don't need every dwarf I meet to talk like in Lord of the Rings. But I do need to know if he's a friendly tavern-keeper, or a clan leader who commands respect.

If you've never GM'd before, don't worry about voices for individual NPCs. You have enough to worry about learning in the beginning, and unique NPC voices is more of an "icing" on your GM cake. Not doing voices will not break character immersion, and you can always throw it in later once you have the experience.

This video from Matthew Colville talks a lot about NPCs and roleplaying them, including the topic of doing "accents" for characters. Probably a great watch for this exact question you're tossing around in your head.

Absolutely not important. What is important is the npcs role in the story and their motivation for interacting with the PCs. If you want a character to stand out you can achieve that with describing their mannerisms, their appearence etc. Hell, you can even describe their voice if you want. No need for actually "doing" the voice.

Not that much. Manners, how they speak and what they are saying are for me much more important than good acting. I'm mostly acting (hehe) as a narrator until something sticks and it becomes easier to do it in first person. But even then the narrator comes in to clarify and emphasize things. Like if there is anger in the voice. If they avoid a topic.

Also narrating things goes so much faster.

I feel like you dont have to be an actor, but as long as you point out how npcs are acting and how they sound when they speak etc, that works well too.

I do them because they're fun, not because they're necessary.