Also not entirely sure what I would use it for since I’ve mostly seen it with rips of Blu-ray movies and shows, never smaller files. I thought its main advantage was holding multiple video, audio, and data streams.

WebM shows that Matroska is excellent for streaming. It’s the same container, WebM just mandates a set of codecs (just as MP4 as an offshoot of MOV can theoretically hold non-MPEG codecs but nobody supports this in the real world). With formal Matroska support, something like combining a HEVC video track with an Opus audio would be possible.