The purpose remains the same: signing content/proving origin. Obviously AI companies are applying invisible watermarks to prove that content is artificial, which isn't relevant here.

What's lost to you is marketing/advertising. So if you use it as a means to advertise your account then maybe it's not valuable to creators.

I expect another reason to watermark content as a creator is to prevent others from claiming as their own or monetizing it; an invisible watermark wouldn't prevent people attempting those things, but at least it would still be provable.

In this particular case, I can circumvent the watermark with cropping by screenshot. Now it has new metadata and is technically a different image than the original without credit to you, the originator.

Might be a dumb idea, I'm just thinking out loud and getting feedback.🤷‍♂️