It does not use performance-prohibitive dynamic allocation, virtual methods, complex algorithms.
The structural information is statically encoded into the FSM instance type, which removes the need for complex lookups, and internal bookkeeping logic can always access the required information directly.
With memory access being the performance bottleneck on modern architectures, small data structures fit better in memory caches, not only resulting in better performance for the FSM instance itself, and also leaving more resources available to be used by the other parts of the host application.
The tools provided by the library are not restricted to conform to an external standard, and the ideas for the new features come from from both the solutions to the typical problems encountered in development, and competing decision making methodologies, including behavior trees, utility theory and AI planners.
It does not support any artificial standards (including UML), but rather provides tools that make sense in a given setting.
There are no superfluous transition tables, beyond the one defined implicitly in your client code.