Every company that have web and native app should promote native. Safari smart banner is perfect tool.
Tumblr mobile web site goes further. This is the best practice. Don’t just point the user to your native app. Keep your user in a flow by transfering data alongside.
Still, this is not good enough. By tapping link in web app you should transfer not just a link to a specific data to open this data in native app. Web app should transfer the progress that already was made. For example, list from a shopping cart.