I agree with you, I find the insert loops to be perfectly usable. In fairness, I am usually only using one, but in that insert I’ve got a MIDI loop switcher with all of my analog drives and my preamp (the switcher loops are also analog, so no extra latency there). After the H90 I’ve got a stereo cab sim, then it goes to my interface. The resulting 8-9-ish ms of latency is not enough to be significant as far as I can tell.

As you alluded to, it takes sound about 1 ms to travel 1 foot… so if I’m using my DI rig with 10 ms or less of latency, it’s going to feel at least as responsive as playing with an amp that’s 10 feet away. I doubt you’d find many people who feel like they suddenly can’t play with an amp at that distance.

If you’re playing with a DI rig using an H90 and both loops, AND your speakers are really far away, now we might be getting into “problematic latency” territory. But if you’re using headphones, or monitors at your desk or something, or in-ears on stage, there’s really not any reason why the latency you experience should be much different from most other real-world scenarios.

I don’t want to invalidate anyone’s experience or anything, maybe some people are more sensitive than others… just thought I’d chime in to anyone who feels disheartened at seeing latency numbers that seem “big.” The H90’s inserts are definitely usable with analog gear. I’m having no notable issues doing so.