Evolution Simulator in Vue + WebAssembly

I don't understand the trade offs. IIUC the internal values of the blobs are Speed, Size, Sense Range. Why is bad just to maximize all of them?

The evolutionary problems become more interesting when there are trade off, like the a big sizes makes you more difficult to be eaten (that is a good thing) but it makes you slower so other can steal reach the food before you (that is bad).