Speaking of Harbor Fright, I have their 120-VAC "100-PSI 3-Gallon" Pancake Compressor. I believe it's fundamentally same as the Hot Dog version with the same rating. It fits my storage compartment, and that was a big factor in the choice. NOT really adequate for 80-PSI vehicle tires. Great for finish nailing, bike, car, and trailer tires. But it struggles in the 70+ pressure range and will not last for long in frequent high pressure use.
Far from useless. My first one quit after 6 years use and for $40 on Super Coupon sale, I just got another one after looking at the alternatives.