High rep pushups aren't good for much. It's like doing a lesser version of real cardio.
I have been in the military and before that as a teenager could do 15 legit one arm pushups.
One arm pushups and weighted pushups are valuable as they develope real strength and teach you how to increase core tension.
Basic pushups are good when you are out of shape, but once you can do about 25 perfect reps it's time to up the difficulty imho.
My best amount during a 2 minute miltary pushup test was 87 reps. All the way down and back up to lockout.
Big deal. I doubt I could have benched my own bodyweight when I did that.
I also would always severely gas out at about the 50th rep no matter how often I practiced or what style I did. The last 30 or so reps were sporadic.
Some guys could do 100 without stopping.
I think this also correlates to fiber ratio and makeup as I believe guys that do very high amounts without stoppage have higher levels of slow twitch fibers.
One arm pushups and handstand pushups are excellent strength builders and very impressive if you can do reps of either if you weigh over 200lbs.