This would be similar to owning, for example, Apple stock inside your IRA. You can take the stock out as stock, without converting it to cash along the way, but it is the act of taking it out of the IRA that triggers the taxation of the asset or income.
Then, you have a new cost basis equal to the cost that you paid tax on. BTC is about $17,000 today, that's what you will pay tax on if you move it from the IRA to a personal wallet (the exact price on the specific day it happens). Then, any gains or losses in the future will be based on that price, rather than the price you originally paid when you invested in the IRA.
