If nothing else, it's progress towards a permanent manned presence in space.
How so? Space food is >52 years old, and we even have subjects who have spent at least as long as 2.2 years subsisting on it (the current record holder for time in space, Sergei Krikalev). What does Soylent add?
Err, I may not have been explicit enough about independence from Earth's food supply. Soylent is more of a marketing thing than a space food thing, but the approach (don't make food, make chemicals) seems at first glance to be a more promising route.
Rob Rhinehart's food replacement Soylent now has a crowdfunding campaign.
If you're interested in one or more of these benefits, send in some money! There is also a new blog post.