The spring punch of the kind illustrated at your link doesn't usually screw down to produce a sufficient impact to reliably break through - or break up - a modern tempered glass in a single punch. While one of those can spall a small dimple, and punching repeatedly can run the defect until eventually the window will "relieve the temper" (i.e. shatter), a modern thief probably has better tools.
Extra-heavy versions do exist, but they tend not to work very well for their intended purposes so they're pretty rare and wouldn't fit easily in your pocket.
The 5-oz hammer would be about as easily concealable as one of the sufficiently-heavy-duty spring-punches, and much more reliable.
They did work reasonably well up until auto glazing improvements in perhaps the early 1950s or a little before, according to some accounts. They might work fairly well now on common house windows, I suppose.
Of course, I won't argue if you can claim having used one successfully on a recent model. I'd be interested in a trial result (is that a pun?), but unfortunately don't have an expendable window handy, although I do have 4 or 5 of the punches.