I do agree that it is a bad choice, though the reason for this is historical; after quite some testing and comparisons, the best JS-based index I could find at the time was elasticlunr [0]. It may very well be the case that there are better wasm alternatives available currently.
Over time I then added a non-JS, external index. Since I already had an ES cluster running elsewhere anyway and the querying of elasticlunr and ElasticSearch is forwards compatible, I decided to just opt for re-using my ES cluster.
In short, the decisionmaking was a mix of historical and compatibility/ease-of-maintenance reasons.
Yeah, if you already have elasticsearch running it's a good choice. Most people are not going to have that or want to run and maintain elasticsearch though. Reasonable decisions for your situation though!
Over time I then added a non-JS, external index. Since I already had an ES cluster running elsewhere anyway and the querying of elasticlunr and ElasticSearch is forwards compatible, I decided to just opt for re-using my ES cluster.
In short, the decisionmaking was a mix of historical and compatibility/ease-of-maintenance reasons.
[0]: http://elasticlunr.com/