Relative to the use of “Optimize MFi Connection” in the iPhone version of the ReSound Smart 3D app, I received the following reply from ReSound’s Consumer Technical Support when I complained that turning that option on on the iPhone blocked the Apple Watch version of the ReSound 3D app from connecting to the iPhone app to control one’s HA’s:
The toggle switch for “Optimize MFi connection” within the More menu of the Smart 3D app was added to address specific issues with certain hearing aids and connectivity. In general, I would suggest leaving this off as it also inhibits the use of the Finder feature and can also slow down the app opening in general. We are aware that it does inhibit the Watch app and are working to improve this.
The respondent does not say for what brand/model of HA’s the “Optimize MFi Connection” option was added but presumably it wasn’t the ReSound Quattro brand from the gist of the reply.