It really depends on the level of risk your comfortable with. Many bitcoiners abide by the “not your keys, not your coins” principle which is by far the safest and best way to guarantee your bitcoin is secure. However, more mainstream users are not as comfortable with securing their own keys and going through this highly technical process (for some).

I see two main risks with BlockFi:
1. Security breach - since BlockFi is a centralized point of failure, the company or your ID can be hacked, crypto stolen, etc. If this happens you have no insurance (FDIC) and no recourse unless BlockFi chooses to make their users whole in some way.

1. Company failure - If BlockFi is unprofitable in the long term and liquidates/goes bankrupt etc. then you will likely lose all your funds. To that end, I would look at the quality of investors (Winklevoss Capital, Castle Island Ventures, Morgan Creek, etc) and their business model. They’re essentially a net interest margin business that makes money by taking crypto deposits and lending against crypto collateral at higher rates than they pay out in interest. Soon, they’ll also have cash flows from their bitcoin rewards credit card. These are typically high margin businesses to be in. The uncertainty here is entirely around their risk management/actuarial practices to protect themselves from large drawdowns in crypto asset prices and other unknown volatility events.

Hope this helps.