To be truthful, in my case since the RT-AX86U wasn't that expensive I get pleasure simply from the speedier access to the configuration screen when accessing from WAN, at least I am thinking the overall UI response is snappier, I could be wrong though....
I am on Gigabit and also mainly using the router for streaming and accessing the dedicated NAS.
If you have the budget for it, it's certainly not a bad decision. Always better to get better hardware than needed than getting something that is insufficient for your needs.