I haven't done the math, but I'm wondering if this is true. The user can also lose more, and considering the player loses on average, "win much more" seems misleading.
Deposit Bonus increases your odds for higher win
Here too: I'd like to know if this is true (on a mathematical level). This also seems misleading.
Assuming you eat into the true balance before the bonus balance (usually the case, as the converse allows for risk-free gambling esp. if you can cancel) then as long as the expected return to wager through the turnover is higher than the reciprocal of the bonus multiplier.
For example, if the house edge of 1%, accumulated over 40x wagers produces an expected return of 66.9%, then a deposit bonus with an extra 49.48% would be break-even.
In other words, if you have some return R, 1/R multiplies together to produce 1.
Of course, a casino must be profitable. I haven't checked any bonuses on my own, but I doubt they would be particularly +ev, or if they were, it would be akin to the marginal benefit of rakeback or (done carefully) lossback.