Why should I care about USB 3.0?
Is it really just because of speedy external drives (I have no external drives). Why would I need to install a USB 3.0 PCIe card on my Mac Pro? I’ve read several explanations of the difference between 2.0 and 3.0, watched a couple of videos too, but I still don’t understand the real world application for me personally?
Could it really be that I just don’t need it?
Yeah - same boat.
The speed alone. USB 2 is as slow as molasses in comparison to USB 3.
I bought a Sandisk 128GB flash drive which has a read/write speed of 260MB/s. I’m regularly transferring 80-100GB worth of files onto it and then taking it to another machine.
I can do this in minutes. USB2 takes hours.
See, I don’t do anything like that. It seems like USB 3.0 would be wasted on me.
An external HDD can easily max out USB 2.0, even if you only use it for backups USB 3 is waaaay faster than USB 2.0.
The last one I bought was a little while back and was only about $15 delivered, a quick look an eBay turns up this as the first hit:
For less than $10 delivered it’s probably worth installing 
Yeah, ok - I’m nearly sold. 
Will add to my list of things to do, after sorting out the SSD.
I suppose it’s a matter of TIME, time is money.
Waiting for large files to write say around 40 gig over USB 2 is sslloooowwww.
USB 3, wow, that’s better.
It does come down to time, if you have lots of it on hand, USB 2 works just fine.
If you need to be “makin’ the bacon” then faster is $ in the pocket.
Al
I put a Sonnet Allegro USB3.0 card, which was not cheap, into my Mac Pro 3,1. It works fine but I can’t leave any drives plugged into it when I put the machine to sleep. If I do I get 8-12 “Disk not ejected properly” messages when I wake it up the next day.
Yeah, I’ve had similar problems. In fact, on all of my desktop Macs I almost always have to have sleep permanently disabled. I have an old 3,1 Mac Pro limping along which can’t sleep due to the Sonnet USB3 card and the Fibre card.
I echo the sentiments here though - USB3 is significantly faster than USB2, especially with external drives. Once you plug in a USB3 drive you’ll find USB2 a hard thing to go back to.