1) You only get few words / extremely short sentence ... the problem is what your character say afterwards can quite often be very different than what you imagined ...
I wouldn't say "Quite often". It's generally only a small amount of times that games don't present their options correctly. Which can be easily addressed by simply... Not misrepresenting options.
2) You get whole sentence and your character says exactly the thing you just read when you were picking ... the problem is, it gets reaally weird that you have to hear those things twice, also all the voiceactor adds for you then is their own tone ... wich once again dont necessarily coresponds with what you imagined ...
It's no more weird than having a character stare blankly at others who then start talking based on... You telepathically communicating to them?
Having voiced dialogue helps scenes flow better. As conversations become more dynamic, both parties are verbal and emotive, they move like real people do. It gets away from the classic trope of video games where NPC's simply gush out elaborate dialogues to a protagonist that just walks up to people and stares at them.
With voiced protagonist, you are playing character that were created for you ...
With silent protagonist, you are playing character you created ...
In either case, the character is created for you. Even with silent protagonists, the dialogue options are pre-created. You don't get to choose exactly what you say just the same way you don't get to choose how a voiced dialogue is vocalized. You simply are picking pre-made responses that are closest to what you would like.
Unless a game is doing something like using AI to create NPC dialogue in reaction to your specific inputs, you'll only ever be headcanoning that your character is saying what you want (Even then you'd probably be restricted to responses that still follow the game's overall narrative) and the reality is you're playing a character created for you (That you simply have some control over the direction they take)
