Thats because buying such stocks with an IRA account is not generally a good idea from a risk perspective unless you have something solid. You could possibly lose more in the stock then you would have lost in the IRA or gained in the IRA. The banker was simply trying to absolve the the bank from future legal action against them, they have a legal obligation to warn you in certain cases, and sometimes its just because they don't want the money to go somewhere else.
Right now though, probably, investing properly would probably earn more then what the IRA would bring. But to each his own, its your money, but with proper DD and some thinking coupled with common sense you'd probably be fine. So why not go for it. :)
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