I took a quick look. I think those two would be classed as flat-bar road bikes.
They have road bike geometry but with flat bars and wider tires. Both should be fine on hard dirt road. Not going to be able to go places a full on mtn. bike might go. Both have typical road triple gears. The Giant has a little lower gearing. That might be better if you are out of shape and have some decent hills to climb. At the other end, I doubt you will ever use the 52-11 high gear.

Fit is important. Are you comfortable? 5 miles isn't terribly far, but you may want to ride longer too. I find flat mtn. bike bars very uncomfortable. However that is what is in style.

For commuting you want a bike that can handle taking whatever you need back and forth to work. I'd pick a bike that will fit a rack and fenders.

Better. There are many bikes that are "better". How much do you want to spend?

Cheaper? In new bike, I wouldn't want to go cheaper than what you are looking at. Used opens up all sorts of possibilities.