Do I need Wi-Fi or app control on a sous vide cooker?

It's optional. Many specialist-community members on r/sousvide actively prefer knob-and-display units like the Greater Goods cooker and call the absence of an app a plus. Wi-Fi is convenient for remote monitoring of long cooks, but reviewers repeatedly flag buggy apps as the weakest part of connected models, particularly the Breville Joule which requires the app to run.