Anything can fail, the controller could fail in the new herpstats and no longer register the set points. A failsafe is never a bad idea, I have 3 HS pros and one HS 4, 2 and an ND. I have failsafes for all of them. The failsafe is far cheaper than vet visits and Silver Sulfadiazine cream. I still feel the new generation of Herpstats are the only T-stat where it is questionable.
Hydrofarms are not accurate. They have a horrible error specs (4ºF up or down from accurate) add the hysteresis (2ºF) before you even speak of backlash you have a 3ºF up or down range (set at 90º you could have temps between 87-93º). Some feel this is fine others do not. I personally believe 1º+/- is fine but more? NO. My opinion. I personally feel that if you feel the need of using a hydrofarm you should have a known accurate thermometer. There are a few around ones that have a reasonable error amounts (1ºF) Aaron found a 100$ one I have not seen that one yet. There are also more expensive ones but a good accurate thermometer for a reasonable amount is the base herpstat. It is 100$ too, or you could save 40$ (CAD) and buy a herpstat.