I had the same thought so last week I bought the earth auger at menards, brought it home, hooked up to my Jiffy. I fired it up started drilling, but nothing happened. As it turns out the earth auger has a backwards spiral (or some might say my ice auger is backwards). But anyway it doesn’t work. I put my ice auger on and tested it out last night. It worked just fine, much easier than doing it by hand and if I ruin my blade (which I expect I will) it is only $30, much cheaper than even a half day rental.
Hope this helps.