Well, about half the time I use my angle grinder, I'm squatting at whatever it is I'm working on... giving whatever is directly in front of me a nice unobstructed shot at my nuts. I always figured that if one of those wheels comes apart for any reason at all, I'd like to have that guard between the exploding wheel pieces and my nuts. Oddly enough, I've had this opinion since I bought the thing when I was 17, and I'm 39 now.
And one time about 8 years ago, it paid off nicely. The wheel exploded, pieces went everywhere, including hitting me on the inside of the leg up toward my knee... but nothing came back and hit me in the nuts.
I was talking to my Lawson dealer about just this subject last week, and he said he always told on of his customers to buy quality USA-made grinding discs (Lawson, of course), and to keep the guard on his grinder. The customer didn't think either was that big a deal.
The Lawson guy saw his customer at the races one day, and he was kinda hobblin funny. He was grinding on his race car, squatting there, and the stone exploded and...anybody? YES, it hit him in the nuts. Actually, it hit him in the pecker, slicing through a pair of blue jeans. Several stitches on his pecker and a week later, he actually whipped it out to show the Lawson guy, and the Lawson guy said "It was yellow and green and black, had stitches on it, and was about the size of a football!" He made a comment about the guy's wife probably liking it, and the guy said he didn't even want to think about *** for a long time.
So ask yourself... what do you like better? Running without the guard on the grinder for some perceived benefit of increased field of view, or a normal-sized pecker without stitches that's always ready to go?
I find that many of my decisions are guided by a long-term view on the relative health of my pecker. So far, I'm batting 1.000.
-Brad