If it’s worth anything, my Tilt’s temp readings have drifted by ~1degC since I calibrated it about 6-8months ago. If you’re not bothered about the inaccuracy of the Tilt, you may as well be sticking a basic one wire sensor on the outside of the fermentor, imo.
Also worth thinking about the quatization error on the Tilt’s temp readings. I think it’s about 1degC, iirc? It’d be really difficult for BrewPi to keep that anywhere near stable. Esp when it first winds up, when ramping, or during heavy activity.
If you don’t want accuracy, it’s probably worth saving your money and buying something other than a BrewPi imo.