My car battery died in my own driveway on one of the coldest mornings of the year, which felt almost insulting since I wasn't even stranded anywhere interesting, just stuck ten feet from my front door running late for work. My old jump starter pack was, of course, sitting uncharged in a closet somewhere because I'd forgotten to plug it in after the last time I used it.
After finally getting a jump from a neighbor, I compared a basic clip-on pack against this permanently connected option with my mechanic, who pointed out that leaving one wired in avoids the entire "forgot to charge it" problem that had gotten me in the first place.
It's been installed for months now, and the one time my battery started acting up again, it just worked without me digging through a closet for a dead battery pack. Having it already connected turned out to be the actual selling point, more than any spec on the box.
