His peers thought it was magic because they were unfamiliar with the concept of writing, not because his writing system was so efficient. He was put on trial for witchcraft because people thought he was communicating via magic. https://education.nationalgeographic.org/resource/sequoyah-a....

The syllabary was widely lauded, as its phonetic accuracy and simplicity made it far easier to grasp than English.

I mean, that feels like it's bound to happen when an alphabet is built to represent current language or pronunciation. English is notoriously awful for not doing that.