What is a bitcoin deposit bonus?

Could you please elaborate on what a bitcoin deposit bonus entails? As a cryptocurrency enthusiast, I'm curious about the incentives offered by various platforms to attract users. Specifically, what is the purpose of offering a bitcoin deposit bonus? How does it work? Are there any specific terms or conditions that I should be aware of before availing of such a bonus? Do these bonuses vary from platform to platform, or is there a standard format? Additionally, how do I know if a platform is trustworthy enough to offer such bonuses without any hidden risks? Thank you for your insights on this topic.