Yes if only you know how you can pay the without touching the bitcoin you have bought with the loan. That is if there is any other alternative to pay the loan then it is a good idea to take loan and invest in bitcoin. Because probably the present time you want to buy or invest on bitcoin, there is no money and you know that money will come in the short period of time, and bitcoin price is very low for you to invest at that time, mate I will advise you to collect the loan and invest then when the money come, you pay back your loan. And of there is charge remained after the repayment of the loan, you can still used the remaining cash to invest to add up the first ones.
But if you are planning to repay your loan from the investment then I will advise you not to take the loan. Because it might land you in a very big mess.
A bit strange logic, if there is another source from which a person makes a profit, then it is better to buy bitcoin from it right away. In any case, you will have to pay interest on the loan.
And the price has already risen well from the bottom, from the lowest point the price has already grown by more than 40%, which is a lot and there was no correction. Therefore, now is not the safest time to take a loan to buy bitcoin.
In addition, will play a role, at what interest you can take a loan, one thing if 3-5% per annum, and another thing if it is 30-50% per annum. I don't like the idea of taking out a loan to buy bitcoin, anything can happen, and person can end up without bitcoin at all.