Your break down about opting for a loan to invest in Bitcoin is understandable, first of all we should know that Bitcoin is a volatile asset and also a long time investment so we shouldn't hope on our Bitcoin investment to pay back our loan there should be a different means to pay back and not hope on our Bitcoin investment.
The ability to pay back is really what matters no matter the outcome of our Bitcoin investment one should not borrow money if the hope of paying back is through your Bitcoin investment it is better not borrow because you won't like your self when the time to pay back has exceed.
Yes, it's not wrong to borrow money to invest in Bitcoin if you are very sure you have a good means of repaying your loan before the repayment time elapses so that it will not attract additional interest and force you to sell your Bitcoin investment too early so that you can repay your loan and save yourself from any problem or embarrassment. So since Bitcoin investment is a long term investment, it is never advisable for someone to take a loan with the mindset of repaying his/her loan with his/her Bitcoin investment because that person will end up selling his/her Bitcoin investment to repay his/her loan.
When taking such a decision, it's mandatory that you are sure of your financial status and your ability to pay back from another source. Anyone that took a loan to invest in Bitcoin without being 100% certain of his ability to pay back from another source is just gambling with his Bitcoin investment which will never ends well for his investment, because the intention of taking a loan in the first place was to leverage on a situation at hand, not from the place of lack, so if you are not sure of your ability in paying it back according to the agreement of the loan, then I would Advice you don't take it because that is like gambling with your holdings, and it is what we all should avoid by all means, because at the end of the day, you might be far be in a worse situation if you decide to take such stupid risk.