>Did OP claim this? I didn't see it, unless deleted on edit.

It's implied, otherwise what's the point of his post?

What is someone trying to achieve by drinking entire meals in a shake, if not optimal nutrition? What other benefits are there?

Having done the Huel thing, it's incredibly low-effort. If you don't value the time spent converting ingredients into a meal, or in expending decision energy either on what to buy or what to prepare, it's a pretty big win.

Time savings