To the OP, IMHO those combination devices are toys.
It might get you through in a pinch once or mebbe twice, but they are not serious equipment. At that size, you might make it work a couple of its functions a couple of times, but I wouldn't expect it to last over a year, the internal battery will die, and then its dead as both a compressor and a jumper.
Sadly, IMHO devices that promise multiple uses with an incredibly small footprint do not do any of its functions well, nor for a reliable length of time.