I used to have a Miaomiao until I upgraded to Libre 2.
It was great to use my phone as a CGM with Libre 1.
My MM lasted a year and then the battery life plummeted to a few days rather than 10 to 14 days.
With Libre 2, Android phones can be connected directly by hi-jacking the Bluetooth signal and directing it to xDrip+.
Some phones seem to have some issues holding the Bluetooth signal. Samsung phones, for example, are renowned at having Bluetooth problems but this may just be because they are most common brand.
So, back to your question - Miaimiao was worth the money for Libre 1 but unnecessary for Libre 2.