If you wanted to anytime upgrade to Pro to be able to use XP Mode
along with Windows Virtual PC
to test programs with, then it could be yes.
A game is not going to run well in a VM since a VM (guest) doesn't make full use of your computer's (host) graphics card and other hardware.
If you already have a legal ISO file of XP or a XP installation disc to create a ISO from, then you could just use VMWare, or another VM program, to have a XP VM to use without having to upgrade Windows 7 to save money.