I'm wondering if "safer" is maybe not the best choice of words for a Gear/HST debate. HST is more of a convenience/ease of use item for alot of people.
Whether a tractor is a gear or hst, makes no tractor any more or less capable. Both can pull a blade, a plow, a mower, use a loader, a backhoe, etc.
There maybe be a steeper learning curve with a gear trans (not for everyone mind you), and more coordination is probably required with a gear.
As stated, there are also transmissions like the PowerReverser, which are probably almost as convenient as the HST. It's completely personal preference for the trans.
Just this past weekend, I was reminded of another reason I got a HST, I was working on our pool, and needed the tractor backed up. My options were, have my 2 year old son, 5 year old son or wife move the tractor. None of them have ever driven my tractor (I was doing something critical at the time and couldn't move it myself). Logically, I picked my wife to move the tractor. Thank God, I have a HST, as my wife has ZERO coordination. She successfully backed up 15 feet and even lowered the FEL too. 8 years ago when we were dating, I had a standard transmission car, and I thought it would be fun to teach her how to drive one. Well, she never really got the hang of it, just a complete lack of coordination. In a complete emergency, she could move a standard trans vehicle, but that's it (it wouldn't be easy). If I had a Gear tractor, I would have picked my 5 year old son to move it.
Another reason for me getting HST is I'm rather impatient. I wouldn't enjoy my tractor as much if I had to stop to change directions/speed, actually it would drive me nuts.
I was able to use a Ford 1910 gear trans for a day, backfilling some trenches. While the tractor was more than capable for this, I knew I wanted a HST when I bought my JD4300.