I agree with all of the above. It does take away fine control and you end up with a lower commission too.
It still suited me due to the streamlined process, and aside from that I never did get the apple books software to accept any of my epubs. I couldn't afford to spend any more time on it, and soon afterwards (August last year) I switched to KU exclusive where I've remained ever since.
But before that I was wide for 7 years straight, and one of the things that did get to me was having to maintain so many books (50+ titles) on multiple stores. I love uploading to Kobo, tolerate uploading to Amazon, but the rest drove me nuts at times. (Eventually I learned to live with Smashwords by uploading my finished EPUB.)
I upload at Kobo, Apple, B&N, Google, Amazon, my own website, DriveThruFiction, Smashwords, D2D, PublishDrive, Streetlib and audio at Kobo, Audible and Findaway.
I have more than 60 books.
If you are able to fine-tune your listings on each retailer, they will each bring in a steady amount. I run almost no ads.
You do have to be patient and take each retailer by the horns one at a time. I do use the tools that make it easiest and quickest for me.
But a lot of the stuff you only need to do once.