But I’m only implementing my machine in one language, why would this be useful? When do I need the same machine in multiple environments? Or are you referring to things like tooling for visualization etc?
As @CitizenKane pointed out, reusing statcharts between backend and frontend is a growingly popular use case.
Another benefit is you could use any visual tool (preferably web-based with collaborative capabilities so that all stackholders could work togehter) for state modeling to encapsulate business logics completely in statechart then export SCXML to any language you might be using.
It could be useful in a number of scenarios. For instance you may want to resolve state between a front-end and a back-end, so the ability to make transitions on both could be very useful.