Jaguar is the tooling to enable rapid development. It consists of two parts: one that runs on the ESP32 and another one that runs on your computer.

Whenever a new program is ready, it gets pushed (over WiFi) to the device. The whole process only updates the actual program (not the whole OS), thus making the development cycle really fast.

Compared to MicroPython, Toit is significantly faster. In my (obviously biased) opinion, it's also more robust.

You can't link C drivers directly without modifying the Toit code base, but there is a bridge to talk between C and Toit code. Generally, we prefer to reimplement the drivers in Toit. However, for some bigger ones it clearly makes sense to keep the C version.