I think the sweet spot of text based diagram generators is when the intent is high levels of information delivery at low levels of effort. It is super easy for me to say "a sequence diagram would help convey this concept better" and write up a diagram. Whereas if I had to use a visual tool, it'd be a higher level of effort.

Text based diagrams are also easy to:

* version control

* get feedback on (it's a PR away)

* change

Even though you can style the text based diagrams (see this for plantuml styling: https://plantuml.com/style-evolution ) for a cohesive look and feel, visual based editors are still going to win out. I use them for free form diagrams and also presentations.