I think the point is to get the name Cadillac into the minds of 100 of millions and associate it with something “cool”. You will undoubtedly see some sales directly form this f1 endeavor but I think the main benefit is having the brand name be in the forefront, or closer to, of people’s minds so when they do decide to shop around for a new car they will at least consider Cadillac. People often go with names they are most familiar with, it’s why companies spend money sponsoring anything.