Yeah thats what I have learned from my experience also, but Im not sure so thats partially why Im asking here. Awhile back I had my Stamina system, particularly the regen system based on a Delay that was looping itself, and getting its first call from Event BeginPlay setting the loop in motion. The delay worked, but its accuracy depended on frame rate. The stamina regenerated based on performance rather than an exact amount of time. I switched it later after discovering that, over to a Timer. The Timer is exact and seems to always be accurate. Its from this experience that made me start to get curious about the differences between Timers and Delays as far as accuracy.
As far as my use of the delays and retriggerable delays, many if not most are used to prevent flow until that flow is broken, so that the last call going through finally can count down the retriggerable delay and set off a bool or something. Others are just simple delays there to space out time before something can be done like usual. But the more I think about it, the more I wonder if timers might be better to use instead of the retriggerable delays, since they act very similar but at least I know that the timer is exact. I dont know enough about how these work since I dont know a lot about how they was created in C++. My fear is that someone with a faster running PC might have the delays trigger quicker and give them an advantage in multiplayer, or perhaps the Server and the Clients will have differences handling them because of performance if that makes sense