Erik Darling looks at some internals for us:
Things like Accelerated Database Recovery, Optimize For Sequential Key, and In-Memory Tempdb Metadata are cool, but they’re server tuning. I love’em, but they’re more helpful for tuning an entire workload than a specific query.
The thing with BMOR is that it’s not just one thing. Getting Batch Mode also allows Adaptive Joins and Memory Grant Feedback to kick in.
But they’re all separate heuristics.
Read on to see the extended events around batch mode to help you determine if it’s possible for the optimizer to use it for a given query.