Sezzle looks good!, page-6

The more profit they make the more they can borrow. But the more they can borrow means they could make more profit.

It's a catch 22. But they obviously reinvest the profit regardless.

Profit however is always best for a new company, means they can generate money while keeping costs down.
You don't want to spend heaps and get heaps in debt hoping that the growth comes. The growth will come regardless.