We're replaced our diagramming with it instead of things like omnigraffle as it means everyone has access to tweak the diagrams without having to buy software (and then buy upgrades and plugins), and by embedding the diagram in the .png there's just one file to keep track of.
With PlantUML you usually commit your diagram's text syntax to VCS, often close to the code.
As far as usability, we're never going to agree. I find it tedious, compared to writing predictable declarative syntax.
Here's more info => https://joe.blog.freemansoft.com/2020/10/diagram-definition-...
The shapes libraries are pretty nifty and extensive (just need to turn them on).
Can you provide an example of what you're referring to?
Plenty of examples here.