I think that is a very big NO and very bad idea if you wanted to invest in cryptocurrency keep in mind that you should invest what you can afford to lose knowing that there is a high risk when dealing with cryptos.
It is a short no.
Someone who invests in crypto and using not his own money, he's just making himself into trouble. Investing in crypto is profitable but it takes time and is a wise choice.
Not every borrower has that wise choice so they're likely to end up in debt and losses.
Totally agree with you, only invest your spare amounts so when price drop you will wait for the next pump or wait till price become stable. If you take loan then you have to pay back the amount in shorter period of time so if price drops you can face a loss because you have to pay back your loan! So don’t take loans to invest in crypto as their is fluctuation in altcoin’s price!