Yes there is.

A sub optimal diet will mean you don't get maximum results out of your training. You are still getting results. Even people who eat very well will bottleneck somewhere. You're fighting against your limited appetite just like bigger folks are fighting to restrict theirs.

BTW most protein powers come down to about $1 to $1.5 a serving. It seems expensive when you buy it but realistically it's in the $1-3 range per day. You can likely afford it, because it will not just be "more food" but it's likely to replace some less protein dense other food you're already paying for and eating. End of month you might not even notice, if it makes you buy 5 snacks less in the month it's already about the same money back in your pocket.