If any app is going to help me build habits around 3D Touch, it’s Tweetbot. I’d say it’s still slow going so far, but I’m definitely using the feature far more now that my most used application has support for it.
It’s also worth pointing out that hours after 4.0.1 was released, Tweetbot 4.0.2 hit the App Store. This update added the ability to dismiss Safari View Controller by swiping from the left side of the screen — Tapbots certainly isn’t letting grass grow under their feet.