Sense of purpose
Many robotkin are drawn to the identity by a sense of purpose that can be attained by being a machine.
Machines in real life are designed and built to perform, and normally excel at, a specific function or set of functions. These can range from daily household tasks, to complex operations, to defense, to simple entertainment.
Having a sense of purpose can help robotkin individuals feel grounded in themselves and what they exist to do. Euphoria can be derived from fulfilling that function well.