I think with a knife I would get through it. I only see this as a minor deterrent.

Seems interesting for securing items for a short period of time where it would deter most grab-n-go type attempts.  I would like to see them try to cut that safety strap with something more heavy duty, like a bolt cutter. 

Also, at $149, that's pretty darn pricey. 

I don't know for sure but the material looks to be the same as anti-cut gloves.  They work in the same manner that the gloves resist slices well with moderate pressure, but a stab and a cut will tear right through the material.  I also think a knife could get through it easily.  The lock size used due to the size of the grommet would not allow for a very sturdy lock, but this bag is supposed to be pretty portable.  I agree that it might be good for a quick grab and go scenario but not much more than that.  You can also secure a normal bag to deter a grab and go also, so not sure I see the utility of the bag.