Newbie looking to get money back on first purchase

So we’ve purchased our first multi family cash, and are almost done with needed renovations. Soon I’ll want to refinance to get my money back and repeat. I’ve always heard the refinance discussed as a mortgage - but I’m wondering why not a Home Equity line of credit instead? With a HE I should be able to get 70-80% back, and it’s more flexible - you only HAVE to pay interest, but can pay off sooner by choosing how much to pay back each month. Has anyone done this versus a straight mortgage, and what are the pros/cons? Is there something I’m missing?