No, I am not that good, just at my age and injured condition, I won't be going far. Too many limiting factor. Strength training benefit me more at this point.I don't understand this. Are you saying that you cannot get any better due to age, or that you have so much skill and experience that there is no room for improvement? I assure you, both statements are wrong.
I have more than a few years, in life as well as MA, and over the past few years I have come to understand my art more than the previous 40 years. And, I have improved in some ways physically as well (thanks to that greater understanding).
If you are a 3rd, 4th, 5th or even 6th degree black belt and think you're at the end of the road, your education has been lacking for not giving you the tools to realize how much more there is to learn and even improve certain physical abilities and skills.
You are free to feel satisfied with whatever level you're at. I'm a believer in free will. Weights are good (I had a good workout this morning). And they are simple to do. IMO, MA takes a lot more conviction and will power. Doing weights is the easier path. But the harder path often yields greater rewards.