My father, an attorney, made extensive use of the magcard selectric. He did wills and trusts which required revision based on client feedback or life changes. The ability to edit the document from a saved copy was revolutionary in the early 70's. It also supported stop codes so that the system would print, stop, allow for manual entry of a name or other text, and continue. The client would receive a correction free typed document (no whiteout). All these capabilities are normal after the advent of Wordstar, WordPerfect, Word and others. Having typed school papers on this system helped me understand computers early on.

I love how after Jane has her copy digitally recorded on the mag card — she then manually writes metadata on its folder, and files it away...

The future was then, it just wasn't very evenly distributed.

The Mag Card was essentially a word processor, and did not compete with the MT/SC. But IBM also introduced a Mag Card Composer, which did. There really were two very different use cases: general-purpose word processing one one hand, and composition on the other hand. The latter implied proportional spacing, justification, good-looking fonts, and accessories such as high-quality paper and specially-formulated ribbons.