The pump bag is not only used to easily fill the sleeping pad, it also serves as a transport bag and, together with the sleeping pad, provides a place to sit. It is highly recommended if the sleeping pad is frequently filled with air.
Only the weight information on the packaging (77g) is incorrect, but I also put the real 95g in my backpack.

Heiner (05/03/2019), Germany
Orders: 1
Reviews: 1

the object is very cumbersome to use and wastes a lot of time. the contact between the bag and the mattress is very unstable, it takes very little to unhook it. to use it as an armchair, it must be filled with clothing, nullifying the lightness of the bag.
I absolutely don't recommend it

alberto (14/09/2017), Italy
Orders: 2
Reviews: 1

Pump bag with additional benefits!
Once you understand the mechanism and handling, inflating the mat works well compared to inflating it with your mouth.
The bag can be used as a stuff sack when you're out and about, so you have the feeling that you're not lugging anything around with you for no good reason: a clear advantage. "Collecting air" is more time-consuming and "fiddly" than using a normal pump, but it's hardly any weight and packs down small, and the mat can still be inflated quite quickly.

The seat function with mat is nice, but I don't know if I will actually use it in practice...

Stuff sacks do have their price, but I still found the pump sack to be too expensive in terms of price/performance, so it clearly loses one point.

Maike (24/07/2015)

The pump bag works well, with about 3-4 fillings the regular mat is inflated (it would probably go even faster if a nice gust of wind blew air in...)
It also functions as a stool and, although it is quite large, it is still usable as a pack sack.
This means you don't have any extra weight from another inflation pump.
However, I am curious to see whether the opening that you put over the valve will last long and not wear out. It is simply a hole in a strong plastic film.

Ulla (23/07/2015)