To get loan from Bank one has to full-fill lots of formalities before his loan is approved. You can get loan from bank to buy a car or for mortgage but there are not many Banks around who are willing to give you loan for Bitcoin investment because Banks don't like Bitcoin. Having said that even if there is Bank willing to give you loan for investing in Bitcoin then don't go for that option. Investment in bitcoin is not doubt profitable but over longer duration and there are certain rules and regulation of Bank loans which a borrower has to follow like you have to pay the instalment on time. There are chances that you invest in Bitcoin and price goes down for long duration, then as a borrower you have to pay the instalments along with interest from your pocket.
Many people take a loan for investment or business, most people treat Bitcoin as an investment, even banks hate Bitcoin, I don't think they won't give loan when you have valid collateral. Have you ever took a loan with a purpose to invest in Bitcoin?
The banks will reject your loan if you said the money will be used for gambling, as we know in the long run, the gambler will lose.
As long as your income enough to cover the installment and interest, even holding for long term won't be problem.
If you know that the bank will approve you for the loan you borrow from them, there is no reason for you to say that you will use it to invest in bitcoin, you can say another reason that they can accept, then is it mandatory for the bank to say the reason for which you will use it?
Because as far as I know, the bank is out of the question as to where you will use the money they will lend you, because what is important is that the bank knows
that you are capable of paying them back in the end.