This is more with regards to pre-ordering, but the main reason to avoid buying a game on release day is quality issues. Essentially, you are buying something before anyone has the chance to review it, which is a leap of faith.
The only tangible reason for pre-ordering is for the "bonus" content, which is typically not worth gambling on a potentially mediocre or flawed release.
On the flip side of that, the real reason for pre-ordering is in support of a developer or franchise you have a high degree of faith in as pre-orders can effect the release of a game with regards to its success. Positive pre-order data does actually help developers.
As a consumer, the general reason for buying on release is in response to a long anticipated release that the player wishes to experience along with all the others who were waiting and wish to immediately express their opinions on said release.
Personally, I have bought far too many games on release day that ended up in the backlog that would have been better purchased later for less or not even at all and believe that the best policy is to buy what you plan to consume immediately.







