That's how I use it too. The actual "editing" bit is far less important to me than rig/performance management. However, I think what GS was saying is that if you are using it as we do you probably aren't changing in real time the way you would with a footswitch so a little latency isn't an issue. By the time I have reched for the keyboard, clicked a new profile and returned to my guitar the rig always has time to change.
Yes, you're right. But if you navigate through performances instead of rigs with RM3 connected, there will be latency between the slots of the performance when you play guitar. This latency is far less present with the official release version of RM, I think.