A puncture is a PITA at any time - fixing it just a further headache to deal with when travelling.
Last Friday my wife picked up a screw in a tyre and even though it was still in the tyre, pressure wasn't holding up too well. A modest 30 minute urban drive home, after inflating the tyre to the recommended pressure, saw it lose more than 5 psi. Then after it was parked and reinflated, an hour later it lost about 7 psi. Luckily our handy tyre centre is not too far away and a quick trip fixed it.
Don't rely upon the nail screw in the tyre to be leak free or remain in place. You could use tyre weld, but as noted elsewhere on this and other forums, it's not without issues unless it's possible to wash it out with water - then waiting for the tyre to dry before refitting (if it's salvageable).
When I first got my Z4 I was reading all I could about running with non run-flats, because that's what mine came with. Slime was mentioned a lot and I think it was said that the BMW emergency repair kit was a rebrand of the Slime kit with inflator. Even though it claims to fix holes up to 6mm it recommends no more than 100 miles before making a permanent fix.
I found
Smarbear (Rob) on this forum recommending rat's tails and though it can be a pain to take the wheel off to find a hole, if the nail/screw is still in there it's a straight forward to seal the hole and have an almost permanent fix (which it isn't). If the nail/screw isn't in there then the old trick of spraying all over the tyre with very soapy water will find it.
I just came across this video from Fort Nine comparing a few tyre repair methods
https://youtu.be/Qm6fTWaj3QE
Cheers!
Andy