[pzhon]

Poker sites see much less money withdrawn than deposited. On average, each dollar deposited might be wagered 10 times before a lucky/frustrated/winning player withdraws it, with the rake reducing the dollar by a few percent each time. So, poker sites assume there is some value to having a dollar deposited, perhaps $0.35.

From a winner's perspective, this may seem strange. We know our deposits will not necessarily be churned 10 times before a withdrawal. However, the bonus offers also go out many losing players who make deposit after deposit, and almost never withdraw any money. It's possible that over 75% of the money these players deposit will get converted into rake, balancing out the 0% from a currently active player who will deposit for the bonus, clear the bonus through normal play, and then withdraw the excess.

Be thankful that most poker sites do not yet distinguish between the valuable losing players and the worthless winners. However, some do, and more will in the future.