Even for a startup business, I can't advise anyone to borrow up all the money and start a business with it; it's too risky. The interest rate is attached to the amount on one side, and the risk of the new business, which will definitely incur losses, will mean a startup paying off monthly or weekly debt from the same business will only drag the business down more.
It isn’t advisable to take a loan to invest in Bitcoin or even some other risk; it is not worth it because nobody knows how the market will turn out. The crypto is very volatile, so I don’t think there is a point in taking a loan to invest in Bitcoin, although I understand that there is a gain in it, but instead of taking a loan to invest in it, I would rather use my source of income to be accumulating Bitcoin gradually till it reaches my target.
Cases where I can only advise anyone to take a loan to invest in Bitcoin or any other investment are if they already have an alternative option to repay the loan back and the investment they made will appear to be the second choice, which, if there is not enough profit to cover that loan and interest from the investment, your first choice will come into play and save you from the drama.
The fact is that if there is an alternative to paying back a loan, why take the loan from the first place? You should use that alternative to invest in bitcoin or whatever you want to invest in, because even if the interest is something you should consider, if you have a way of paying back your loan, you should just use that option to invest. Rather than investing all at once, you can accumulate bitcoin gradually.