parent & child compartment on Deutsche Bahn

I'm more curious about the amenities of it. What makes it different from a regular compartment?

This:

A special parent-and-child compartment with play area and baby changing facilities is also available.

Was lifted from here: http://www.germany.co.za/transport.html

It really depends on the class of the train in question:
on modern long-distance trains (especially the ICE class, but also newer IC and EC class train models) the family compartment is worth it if you have small children, because it has room for strollers and is near the diaper changing table.
The dichotomy "family compartment vs regular compartment" is somewhat false on these long-distance trains though: most trains modern enough to have a special family compartment, don't have have regular compartments anymore, just open coaches. The only alternative is to reserve the four facing seats around a table.

On older regional trains (IRE, RE, and RB class) the family compartment is often just a normal compartment set aside for passengers with small children (because one can not reserve seats on regional trains).

That helps so much -- thanks!!