Yeah true. And Luke only uses stuff like that extremely fast "it looked like he had four sabers at once" thing on rare occasions, not for your average duel. I think Obi would be a little amazed at Luke's power if he saw him at full throttle but he probably won't here. And some of those things are actually seen as too out of ordinary and kinda ignored. Black Fleet stuff.

Poor Obi, he didn't know asking about their meeting was gonna lead to hearing how he died.