This is a controversial subject - the term for the structure is "One-True-Lookup-Table" (OTLT). It's a valid model, but I'm confident it's not the enterprise-grade best-practice it might look like.

This post from spaghettidba gives some good comments on the idea. I choose not to lock-in to this model (primarily due to it being non-standard, and difficult to add constraints to) and the majority of blog posts seem to weigh-in against the idea, but many people claim to have used it successfully. I can see benefits, mainly avoiding the schema growth that comes through many small lookup tables. I wouldn't mind it a new employer requested I implement a structure like this.

Andrew