It wasn't so much of a drag in the past when MM rates were higher. There wasn't something ALWAYS inherently wrong with holding a lot of cash.
I agree with you that now a days you want to park some of it somewhere else. It may just be semantics but I don't think high yield should be the place to park it.
I think you want to park ( excess) cash in LOW VOLATILITY investments like short term bond funds yielding at present time 2.5 % not in a high yielding stock fund. SMHB would be an example of the later and look what the price of that did since January.