Note my use of the word many in my post; I did not use the word all!
FYI, I have been successful in the futures market for well over a decade, with zero margin calls and nary a major drawdown. One reason is that I use leverage wisely, and sometimes futures traders blow up due to not using size carefully acccording to volatility, etc. I often use micros, especially in my Roth IRA, where they are usually perfect for my needs.
From my perspective MANY micros are quite successful and very usable: All 4 CME stock indexes, at least 3 currencies, oil, gold, even Bitcoin does alright. There are plenty of days where the volumes on ES and MES are pretty close. I also like the mini VIX. I am glad they all exist. Each to his or her own thing! It remains to be seen if micro copper will do well, after all many futures traders don't even trade copper anyways. Regardless, I applaud CME's experiment.