As mentioned above, some safety features make sense, others do not. In case of the reverse safety switch, I'm sure that was done to appease the lawyers. Deere does have a big legal team, and they probably do keep busy from the sue happy lawyers out there. I read of a case where a guy's family sue Deere when the husband was killed when his green tractor flipped over. It seems though he did not read the manual when it said to use rear ballast when using the front loader. Case was settle out of court.
So, I'm sure that the industry lawyers force the reverse safety switch on the engineers to try and reduce lawsuits. All manufacturers, or all the ones I know, have some sort of safety feature to prevent mowing in reverse for residential owners (notice that feature isn't on zero turns, or at least the commercial ones). I would say it probably distracts the operator from peeking over his shoulder when backing up.