This has been studied to death, and documented, just as much. It's been known that no serious athlete would forego resistance training, for a couple of decades now.
There are a long range of benefits, which you can find in all research available on line.
This is something that doesn't need to be hearsay. This has been studied for decades, and there's a mountain of empirical evidence.
The best of the best always incorporate resistance training for its many benefits.
Increased / preserved muscle mass, as you grow older.
Better power generation.
Neurological conditioning, as with the proprioception, but, more in line with developing a better nerve.