Nothing, for now. In the near future you will be able to send digital flowers for a fee. Other paid services and monthly fees are also possible.
Is there a Matriland app?
No, and currently there are no plans for one.
Why don't you ask for the email address?
Usually, the email addresses you use for subscribing to various sites will, sooner or later, stolen or not, be bought and used for mass-mailing. We don't want to support, even without intention, this type of business.