Hello Shade,
You've provided an excellent overview of the distinctions between enrichment cultures and selective cultures! Your explanation of their goals and techniques is very clear.
To build on your insights, enrichment cultures are particularly beneficial when the microorganism of interest is found in small numbers in a sample, as they provide an environment that favors its growth. Conversely, selective cultures focus on isolating a particular organism from a diverse community by employing media that selectively inhibit the growth of unwanted species, facilitating the study of the target organism.