Why is the app icon different from the brand icon?
We like to make separations between our commercial endeavors and our open-source endeavors. Our apps, both on desktop and mobile, are built to be long lasting, and represent not us, but you, and your work. Therefore, our apps do not make use of heavy "Standard Notes" branding. Instead, they focus on fulfilling a utilitarian purpose separate from what our commercial interests may be.
For that reason, Standard Notes makes use of two different icons for representing itself throughout our ecosystem. One icon is the curved white 'N' on a blue background, and the other is a traditional app icon that looks like a notepad.
The N icon represents the Standard Notes "brand", and is used on our "commercial" side of things. For example, on our website and Twitter.
The notepad app icon is used to represent a place of notes, and not a place of business.
While we may benefit from using the 'N' consistently in terms of brand name recognition, we fear that in doing so, Standard Notes shifts gradually from being a user-aligned safe space, to a commercial property that attempts to insist upon itself at every given moment.
Ultimately, we built Standard Notes to be yours, not ours. This is why it is open-source: if we, as a commercial entity, perish for whatever reason, Standard Notes the app will not perish. Only the 'N' will.
As for our simple notes app: we wish it to remain alive and independent for centuries to come.
Bonus question: Why does the desktop app have a blue tint, while the mobile app has a red tint?
This is ultimately subjective, but we feel that blue feels comfortable and safe on desktop, whereas red would look too "danger" colored. And on mobile, we feel that red is intimate and safe, while blue is too generic and cool.
Also, we use these color distinctions to ultimately convey that while both these apps bear the same name, they are not 1:1 in terms of features. We aim for our mobile app to be a companion app to the desktop app. So, some features, like certain extensions, are available on desktop but not mobile. In the future, this gap may narrow, and feature parity may converge, but it remains to be seen whether this affects the tint of the apps.