As a vegetarian who regularly makes curries from scratch, from soaking the lentils to grinding my own spices from whole seeds/pods and grilling paneer in tandoori paste, I can say it doesn't hurt to have the option when you've feel like having a burger, and it's a good way for people who want to make the switch to vegetarianism to know that their favourite junk foods are still an option.
It's even more important for legumes and other foods because it removes phytic acid (one of the things that prevents absorption of nutrients/minerals) and makes it easier to digest. It's similar with nuts too. They all become nutritionally more accessible (and "richer") when soaked and the soaking water is later thrown out (before cooking).
