Why?
I've been making a game Return of the Lividaea for some time. When I started on the dialogue I purchased the Dialogue System for Unity, which was very powerful and had loads of features. However I found the node based system very slow--write a line, move hand to mouse, create new node, write a line, repeat-- but, I saw that it had integrated support for other tools and found Ink.
Ink is fantastic, and you should 100% use it over topiary.
I really enjoy writing in Ink. I had a few issues with it, but all in all it's fantastic. But in the summer of 2023 I picked up Robert Nystrom's Crafting Interpreters, once I finished with that I immediately grabbed Writing an Interpreter/Compiler in Go by Thorsten Ball. It was so much fun writing a language I decided to adapt them to a dialogue scripting language and topiary was born.