That’s correct. But bear in mind that sadly that Rawpedia page is outdated.
To take a look at the current «cli» options you will have to run: rawtherapee-cli -h (if RT is not present in the system path, then you will have to launch it from the folder where RT was installed).
It «does work» by coincidence: most probably that option will be ignored by RT, and all you will have is a fallback to defaults, which in your case are what you need: default is 16bit tiffs.
The correct options (to get the same result as with the defaults) are: -b16 -t
Last time I checked, the cli help reads as this:
-b<8|16|16f|32> Specify bit depth per channel.
8 = 8-bit integer. Applies to JPEG, PNG and TIFF. Default for JPEG and PNG.
16 = 16-bit integer. Applies to TIFF and PNG. Default for TIFF.
16f = 16-bit float. Applies to TIFF.
32 = 32-bit float. Applies to TIFF.
-t[z] Specify output to be TIFF.
Uncompressed by default, or deflate compression with ‘z’.