In my opinion I would say yes it is too course. If you wanted to shoot at 1200 yrds, each click will move you 12 inches. With a 12-16 inch vitals target, that doesnt leave much room to be off on your clicks. you would have to adjust your hold to split the difference. The norm seems to be 1/4 moa clicks. now you would be 3 inches per click at 1200 yrs.
From what I have heard the M3 turrets are favored by the tactical guys because they are fast in urban situations.
Yes, I think they are too coarse. We use them because that's what the Army gives us to use (w/BDC elevation turret). Not any faster if you ask me. The BDC might not be on, so you need to keep up in your data book. If you keep good data you will know to "favor" high or low at distant ranges.
Example: On our unknown distance range a couple months back it was my partner's turn behind the rifle. At a mil-ranged distance right at 740m my partner wanted to try a head shot. I told him to put 7+4 on elevation and 1 1/2 minutes Right on windage and hold at the crown of his head (because I had written in his data book at that distance the round impacted about 1/2moa low for our given conditions). GOOD HIT! The guy on the glass thought it was a fluke, so we did it a couple more times, and then at various ranges. My partner's new nickname is Mr. Headshot.