The Btrfs SSD mode had no impact on the LZMA compression speed.
The GnuPG file encryption speed, which is largely CPU dependent, was not impacted by the SSD mount option for Btrfs.
With the Java-powered Bork File Encrypter, the performance was worse with the SSD mode. It took 40 seconds to compress the sample file with the default options while the SSD mode took 50 seconds. Would disabling the write cache or toying with other mount options allowed the SSD mode to operate more efficient and come in under 40 seconds? We will know soon enough.