That’s pure theory without practical use!
Without exception/finally handling you cannot use reliably lambda functions. See my other thread https://community.openhab.org/t/lambda-functions-fail-not-thread-safe/51696/2. The bug is confirmed by other users.
I expect documented language features to be working and not get indoctrinate by people who are not used to that a little bit “more advanced” features.
The exception handling worked more stable in OH 2.1 than in OH 2.3.