Things can go wrong?
I like the switch idea.
Well, if you already have the switch, then nothing will go wrong. 
+1
I recently started using a Blichmann 14.5 gallon conical and I have to say they are worth it. No more racking into the secondary, easy yeast removal and cleaning. A big +1 for conical fermenters. 8)
Those seem pretty decently priced compared to other conicals. However, cooling isn’t an issue for me. It’s heating that can be a problem. They designed their 14.5 to fit inside a stand up freezer - but is there a way to temp control the inside of that feezer warmer instead of just colder?
I’m not that familiar w/ using a fridge to hold a fermenter temp - unless I want to hold it at a lower temp (50 degrees & below).
A digital controller will regulate the temp for fermentation within 2 degrees or better depending on the controller and settings. Johnson controls or Ranco make them for less than $100 dollars.
What I wanted to know was - can it hold the temp around 70 degrees (when it’s 40 degrees outside at my house)? Depending on the ale being brewed, you want to hold at 65-74 degrees. Can a fridge/freezer do that w/ the controller settings?
It can if you put a 40 watt light bulb in it and connect the light bulb to the controller.
OK. Simple enough. Time to start saving up, I guess! lol
The RANCO is easier to change from heating to cooling.
+1
I was also going to recommend the Ranco dual stage (heat/cool) controller but you beat me to the punch. 