A Table is data, don't make things unnecessary complicated. Some data are better managed directly in a table, if you have a good table interface, others are more natural managed in separate files. Each case their own.

And how does mdld differ from dataview?

Huh! I hadn't seen dataview before, I'm more than happy to use another work if it's a supported superset. mdld is sort of inspired by Semantic Mediawiki, dataview uses SMW's :: notation, which is a good sign. However, I don't see a few features that mdld has, like concepts, which are very useful, and the hedgedoc application of mdld has some nice dynamic views, for example, creating a gantt chart out of data dispersed across markdown files. In general, its emphasis is creating things out of data to support features like round-tripping, rather than creating self-contained black box information views. But its more of a proof of concept, so I'm going to look at adopting dataview.