This is just the end point of it, when using a borrowed money to invest in Bitcoin you don't plan on paying back from the profit you make from your holdings, you pay back from another source, that's why I made it very clearly that if the loan is being payed back installmentally from your paycheck it's quite cool, especially if the interest is on the lower side and it's spread out across three to five years payment, but if the interest is high and you planned on paying it back from your holdings, it's a no no in my own opinion, because it's a terrible mistake to be making in this age and time.
Personally I don't support the idea of someone borrowing to invest in Bitcoin, I totally discourage such mindset, Bitcoin is not like other investment so it won't be nice for anyone to borrow to invest in Bitcoin, it isn't right for me, mate there are some investment we can actually borrow to invest in but not Bitcoin unless an investor has a good source of income he or she can lay hands on later to pay up the loan just as you said but whats they need of even doing that, instead of borrowing when you have other source to pay back, why not use that same source to keep investing slowly consistently, I don't support borrowing to invest in Bitcoin, Bitcoin investment should be done in such a way that an investor wouldn't put him or herself in an unnecessary pressure that's capable of making his BP to rise, since we understand and know that we can actually invest in Bitcoin with what we can afford temporarily and increase our level of investment when your income comes up, I don't see any need of doing otherwise for no just cause when we can do things gradually,steadily and relaxed without being bothered.
I wonder how people would be so desperate to the point that they'll take loans to embark on a long-term investment, one shouldn't even take loans to risk on coin with short-term gains talk more of investing on a coin that involves the future, either ways the person would end up being in debt and we all know that it comes it embarrassments most times, when the debt is due for Payment and the person can't meet up paying, of course they'll never meet up paying on time and that's the first thing one should consider before making such decisions since Bitcoin investment is something that involves holding for the future. I don't support that idea as well and I feel people who do that are those with a trader mentality cause they won't say they're not aware that Bitcoin investment is for the future, so why take loans to invest of something you'll hold for long-term before making good profits, expect they're only investing for short-term gains like buying during the dip to take profit went it pumps which is definitely a traders mentality.