The money matters because the biggest problem with Shaq is going to be if he causes locker room drama and problems. If he starts demanding the ball and causing locker room strife, you can not just cut ties with him because he's costing you $10 million($5 million for his salary, $5 million for his luxury tax). If he is just a bad fit for the team and has to go, that's $10 million.
Now you might not care about writing a $10 million check for a guy that management could believe might be a coaching headache but ownership certainly will. If he comes in at the vet min(a league subsidized contract that the C's are only responsible for $850,000 plus or minus) cutting him if their are problems is a minor thing.