You have to pick 1 instrument, and that's it. This kinda stinks.
You start with one instrument in your inventory but again, you can play any instruments that you find

Why would I waste an ASI/Feat on being able to play an instrument when it has no gameplay value whatsoever?
It can be used as a distraction (and to gain some coins if well performed) but I understand the sentiment of wanting more.
And I really think it's dumb to gain proficiency because you help Alfira write a song. Years of practice to gain a proficiency cannot be gained in a single session of helping a bard write a song. That's silly to me.
It's a little weird, but at least player have a chance to gain musical proficiency without a feat or being a bard x)
When you are proficient and fail the performance check you still play alright.
👍
I guess allowing the Bard to play anything makes sense. For video game purposes, it's just easier. That works for me. I just wish they provided other options. Like I said, allowing maybe a Background or 2 to have the proficiencies.
But, I suppose the way they're doing it, if it's a matter of all or nothing - you're allowed to play all instruments with proficiency as a Bard, or nothing if not a Bard unless you have the Feat which allows proficiency for all - then yes. That's easier for them to code and it works well enough. After all, musical instruments aren't that important in a game like this.
Still, the Entertainer should, at the very least, be allowed to have musical instrument proficiency as a freebie since it goes along with their background. So, you could be an Entertainer who is proficient with instruments and then a Ranger or a Fighter or something like that, showing that you were once a performer but are now, due to life's choices, something entirely different.