Why is Google allowing crypto ads ?

Its not necessary to use "Actually" Crypto Keywords or Bitcoin Keywords on your google ads, just use other keywords like people intend to invest their money, CAUSE THEY HAVE MONEY TO MAKE THEM DOUBLE, so they are looking for just investment trade module, doesnt matter if you hold a trading company or a cryptocurrency site.

More over once your adcopy is approve on non btc or cryptocurrency related keywords then you can search for related keywords on google same country you will already see tons of crypto ads floating, just copy them with few alteration on keywords of adcopy.

You will not be banned.