Nothing about the tessel seems like your developing low level circuitry. It just seems like another website... that can make things spin.
If you’re interested in playing with sensors, RFID, or relays, you don’t need to worry about breadboarding, wires, and discrete components. Instead, the standardized header allows you to just power down the board and slot in one of the modules. The Tessel team has released node.js libraries for each hardware module, eliminating the need to resort to low-level programming just to see data from sensors or to make motors spin.