To be a successful investor, avoiding FOMO is very important which means you never take loans to make investments because cryptos are not giving dividends then how you are going to pay the interest rates? What if your investment become total failure.
On the contrary, I believe if people are doing margin trading or futures then they are already taking bigger risks because taking 3x leverage means your portfolio will be emptied if the price falls by 33% and considering the volatility of the crypto market it can actually happen within days or even a single night.
I always think that better than taking money on leverage and risk losing everything, it is better to take loans in real life and pay yearly interest because it gives you much more time and the assets/coins you buy are going to be yours 100% without any risk of marketing being down or up.
Consider this as an example:
Trader 1: A trader bought Bitcoins at 8k last year February and he took only 2x leverage, in march as the price dropped below 4k he lost everything he hold.
Trader 2: Another trader took a loan of 8k and bought bitcoins with it, market went ballistic and as low as 3k but he lost nothing and somehow market recovered and now an year later he turned his 8k into 45k now.
So, it might not be the worst idea to take loans for buying Bitcoins, given you have back up plan and good strategy.