If there is any damage to the tyre wall or the puncture is large (eg, a cut) the inflator/sealant method will not work. Even if it does it makes your tyre non-repairable. I've' had my current car for 13 years/200,000 miles and had two incidents. One was a screw in the tyre, which was repairable. The other was a nick in the tyre wall in France which needed a new tyre; without a spare (space-saver) I would have been in a really sticky situation as it was a 40 mile trip to the nearest tyre dealer who would only sell me a pair of tyres and took 2 days to get them. Space-savers are not ideal but better than nothing but avoid sealant/inflator kits like the plague.