The Lutron Caseta switches are very well engineered devices, and I use them in my own home.
But the Master switch doesn’t solve the problem you’ve described, because it still controls the current to the fixture.
If you’re talking about the pico auxiliary switches, those can do what you want if you are using one of SmartThings’ competitor hubs, like hubitat or I think Wink. But the official SmartThings/Lutron integration does not expose the pico devices, so you can’t have them control your smart bulbs.
There is an unofficial integration which uses another server as a “man in the middle” and it can expose the Picos to smartthings, but the setup is quite complex.
But the regular Lutron Caseta master dimmer switch does control the current to the fixture, so it does not solve your problem.