Material Design brought bland consistency to the Android ecosystem. Every app had some sort of bold header and a floating action button. There is some value in consistency and at least some personality was retained. It's red, it's probably Gmail. Yellow, I must be in Keep. Boring but tolerable.
Material Design 2 solves mainly for the problem of knowing which app you're looking at. Colors have gone. Every Google app is now an oppressive black list with some oppressive black icons. To add to the misery the icons have a shade of stock-library amateurism and are just a little too heavy. Unless I look really closely or the what-icon-did-I-just-click region of my brain is on top form there is no longer any way to tell the difference between Google apps.
I'm pretty sure Material Design 3 is just going to be a command prompt. What Android customers really want is telnet or wget and some raw JSON.