That is whay they are called "adventure dives" and do not make for any specialties ... yetAs you pointed out, they are experiences of things to come - much as a test drive. fer instance, the mandatory UW nav adventure tackles the 1st bit of the actual specialty course, with an expansion of what you learned (hopefully) on your OWD course. (in the actual specialty course, you then get to use a nav finder and learn to do more complex routes) .
If you complete only 3 adventure dives, you become ... yeah, u guessed it! An "adventure diver".
Remember the difference between "scuba diver" and "OWD"? Same system.