Only disproportionate gains, not losses. When a startup goes bust, every investor can only lose what they put in. No one loses multiples on their investment.
Leverage is a multiplier in both directions. People do borrow money to invest in bubbles which is what can make the eventual pop so economically devastating.
It is generally a portfolio investment approach in which you would invest in multiple coins in the hopes one of them gains 100x and you lose your money in the rest. If you think it is so easy and there are only gains to be had, why don't you go ahead and make a few investments and come back with results?
Leverage is a multiplier in both directions. People do borrow money to invest in bubbles which is what can make the eventual pop so economically devastating.