The use case for this app (Dull):

1. Uninstall Instagram

2. Install Dull

3. Use Instagram via Dull

The use case for a Safari extension:

1. Uninstall Instagram

2. Install the Safari extension

3. Use Instagram via Safari

Am I missing something that is obviously better about Dull (which couldn't be replicated by a Safari extension)?

(P.S. this is not meant to discourage the developer of Dull; I like the idea and your implementation seems really good.)