The majority of consumer Optanes—unfortunately—do not support OPAL. The P4800X and P4801X series are the only ones which Intel claims to do so. (I own SSDs from that series and I can confirm.) Now I said “majority” which means there might be one consumer Optane series which supports OPAL: the H20. The drives have a PSID on the sticker, which would only be present if some OPAL-like interface were exposed.
Why have I not confirmed it yet? Well… H10s and H20s present their own host of problems. 
To add to the discussion:
- Straight from the horse’s mouth (Microsoft):
“Typically, there’s a small performance overhead, often in single-digit percentages, which is relative to the throughput of the storage operations on which it needs to operate.” - Anecdotes:
- The Tom’s Hardware article that put the spotlight on the issue:
- https://www.reddit.com/r/Windows10/comments/iibwmn/bitlocker_some_tests_and_thoughts_on_bitlocker/
“I can say that I experienced 10% speed loss in reading, and roughly 5% loss in writing. Interestingly, I didn’t experience any speed loss in random 4k Q1T1 write tests.” - https://www.reddit.com/r/hardware/comments/16nbq7o/nvme_bitlocker_performance_degradation_post_your/
“The 4kQ1T1 was benchmarking really well on this SSD (83MB/s read, 355MB/s write), but this reduced to around 65MB/s read and 156MB/s write post-encryption, at 90% full. I have found that when not encrypted, this SSD benchmarks identically whether empty or at 95% full. The post-encryption result for this benchmark is very similar to my 970 Evo Plus. It seems that there is some kind of bottleneck for these 4kQ1T1 readings.”
- The Tom’s Hardware article that put the spotlight on the issue:
As usual, you’d have to test on your own hardware under your usage scenarios to get the most accurate data.
@mtchetch, you’re either going to have to find your compromise point between Bitlocker tanking performance and NAND having five to ten times higher latency, or self-experiment with H20. 