I was halfway through the article and began thinking that his described data structure sounded very familiar to something I used about 20 years ago.

Sure enough, the first paragraph on the Wikipedia entry for DAFSA is:

DAFSA is the rediscovery of a data structure called Directed Acyclic Word Graph (DAWG)

> I do wish to point out, of course, that the whole reason it was possible to experiment cheaply and come across this serendipity was because 9 months ago, faced with the choice to either do the bad easy thing or the good nothing, I chose to do the bad easy thing.5 The SQLite database worked! I understood how it worked, behind the scenes with its B-trees and its Full Text Search extension.

This is the most important takeaway, imo, and a very valuable technique: Start with the obvious, stupid solution that definitely works. Then do the optimized version, while making sure it matches the naive implementation. In this case, the optimized version could even be generated from the naive one.