Some of the advantages of 5g come from using it as a home connection. My building is locked in with spectrum and I'm limited to 100mbps, despite ATT serving fiber all over town. I can't do anything about it because it would require having a telecom wire our building for their service, the equivalent of moving heaven and earth.
If I could pick up a 5g signal I could opt for that instead. It's like suddenly having an option for installing a dish instead of whatever the cable company serves you.
As far as speed, I'm not holding my breath. In a previous apartment I did actually have fiber but it wasn't the game changer I thought it would be. Downloads and streaming are capped at a point. The only way to actually use all of this horsepower I had was with bittorrent, and boy it downloaded stuff so fast that the write speed on my drive became a significant bottleneck. I even demoed Googles project stream and while that worked OK, I still got a lot of hickups and low quality stream moments that showed how far away the delivery technlogy was (AC:O was playable but there was way too much latency for a multiplayer game to stream with this technology), even if I had the very best internet on the market.
Even mobile phones are now getting 90hz screens, yet we struggle to stream anything with more than 30hz at decent quality. This might not be noticable in most movies, but game streams could be much better and sports events could benefit a lot too.
What are the legitimate new capabilities you're thinking of, which many people desire, but can't have primarily because of (mobile) internet speeds?