It does if you’re computer and the server can keep up. Which is generally not going to be the case. I mostly only download games from Steam, but when I use other PC services they don’t saturate it and Playstation network on the ps4 at least several years ago didn’t even come close.

So ya it mostly doesn’t matter.

Probably not unless you all regularly stream several as in more than one for each of you, 4K videos at once.

Other than that it’s mostly whether or not you want to download things faster. Most servers won’t even give you a full gigabit down. Steam does. So if you regularly install large AAA PC games maybe it is worth it.

If you do a lot of piracy you can sometimes a saturate a gigabit connection with a well seeded torrent.