I don't like that to deposit on the spirebets account you pass with coinbase by paying in USD.
I could experiment, but I must be free to use my BTC / ETH addresses both to deposit and to withdraw.
To withdraw you have indicated the fees to be paid, but it is not known if you pay taxes on deposits.
The 10% deposit promotion is not published on the site.
Finally, a very important aspect is to know the maximum bet you accept, because if you deposit 1 BTC I don't have to have the negative surprise, that you only accept 0.2 BTC of maximum bet