The 1st time I used a Chronograph was in 1989 in Austria. A gunsmith friend of my wife's family was letting me use his range to confirm my zero prior to heading out for my 1st Chamois hunt.
I've been hooked since. I've now got two, and old Oehler 35P and a Labradar.
IMHO they're pretty much essential when it comes to any type of distance shooting. While I believe that accuracy trumps statistics (SD and ES), when it comes to over 300 yds I want both. Without good stats you'll start picking up vertical and horizontal dispersion. IF you don't believe it, just run a couple ballistic solutions with your high and low MVs and watch the effects down range.
As many have noted, the book MVs published in loading manuals often seem optimistic. They're generally using test barrels, long custom test barrels, with tighter than average factory bores. I have no doubt their barrels shoot "faster".
So the normal scenario runs something like this...loads IAW published data, zeros his rifle IAW a ballistic program (maybe, a lot don't bother) and they find out the hard way that there were actually running 100+ FPS slower than book data. The +1.something at 100 to get them a 200yd zero (a lot of guys only have access to 100yds), really should have been +2.something. On the day of the fictional hunt, our guy spots a decent buck at 345, not a problem as he's worked out his dope chart and he holds 10" high, right on hair line (cause he read about "hold on hair" in an old Outdoor life magazine) He then proceeds to hit low and more left than they had hoped as the temps were lower than when they zero'd and that 3 O'clock cross-wind was a little more brisk than he thought it was.
My scenario is a little extreme because in reality our chronograph-less, reloading hunter, will probably pop his deer at the standard 200yds or well under and will never be the wiser.