I'm going to use my RIMS controller to make a water bath in a plastic container (with a different element, temperature sensor and pump) for cheesemaking, which often needs to hold the culturing milk at around 100f. It'd also work well for yogurt, and maybe even bread rising. It could obviously also work as a sous-vide if I use an element big enough to hold higher temperatures. Or I could use the RIMS plus cooler mash tun as a larger sous-vide.
But since I don't eat much meat, and my wife is pescetarian, we don't have as much call for sous-vide cooking as many of you.
I'm also using a copy of my RIMS controller at work to control a cheap lab oven for baking HDPE millimeter-wave antireflection coatings onto cryostat windows.