Algae has what I sometimes call the "hempseed problem": it tastes awful. Hempseeds are highly productive, nutritious, and smash almost every other whole plant food on the crucial protein:fiber ratio, coming in at 12:1. The only problem is, you have to eat them.

Japan pretty much identified every kind of seaweed that you can eat without puking a thousand years ago and the list is not long. A tablespoon of spirulina is a great way to ruin a smoothie, never mind that it mostly comes from the disappearing Lake Chad.

So it's heavily processed, and it could certainly get into food products that way, but nobody will notice — or care — that they're eating algae-derived food products. If you doubt that, just look up where xanthan gum comes from, or consider that Aspergillus niger is the primary source of citric acid.