You're right that picking up the food is rather "useless", but imo it adds a lot to the atmosphere of a level. Simply because it's animated objects . And well, what's the use of the coins? It's not like you're running out of lives right now ;P
I'd really appreciate if you could find the time to continue, especially with some tomb levels. I loved them. "I heard the helicopter leave above me...now I was on my own" :')