I believe a car derives a great deal of its structural resilience directly from the windshield, which is severly impaired by even a small crack.
You will eventually have to replace it anyway, so surely best to do it now just in case you’re involved in a collision some time soon?
DougC do you have a cite for this? The reason I ask is a long time ago I was a qualified glass cutter and AFAIK safety/tempered glass is impossible to cut (its pre-cut from ordinary glass and then processed to strengthen it). I have NEVER EVER seen a crack in toughened glass - as soon as any crack develops the whole sheet goes (and forms those small square bits).
As an aside it used to be great fun cutting laminated glass - we used to do it by scoring and running the crack on both sides of the sheet and then pouring lots of meths into the crack and lighting it to melt the plastic - used to scare the hell out of the customers 
Mind you - it used to scare the crap out of us if the flame caught the top of the meths bottle when we had to add more meths to the sheet. Since the flame was virtually impossible to see you would hear the meths bottle ‘sneezing’ when you put it down and then you knew you had trouble :smack:
Actually, as much as I like posting what I DO know, I gotta admit- nobody can say with surety. In some cases, being forceably ejected from a car saves your life. In most cases, it does not and you risk being crushed in a rollover situation.
Too many variables to state one way or the other, IMHO. Sometimes you die in a seat belt, sometimes you do not. 