When comparing Messenger vs Peatix, the Slant community recommends Messenger for most people. In the question“What are the best Material Design apps?” Messenger is ranked 22nd while Peatix is ranked 40th. The most important reason people chose Messenger is:
Allows communicating with anyone who's a friend on Facebook.
Specs
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Pros

Pro Uses Facebook friends to create a contacts list
Allows communicating with anyone who's a friend on Facebook.
Pro Read receipts
Can see who has seen each message in group messages.
Pro Easy to share posts from Facebook
Integration with Facebook makes it easy to share any interesting posts from the Facebook timeline.
Pro Great UI
User interface of the application is clean, intuitive and easy to overview.
Pro Get notified about new events from event organizers
Unlike other ticketing systems, Peatix will inform users whenever the event organizer the user is following just created a new event. Users have the ability to follow the event organizer regardless of whether they booked a ticket with them or not.
Pro Direct messages from event organizers via Inbox
Inbox is a feature where event organizers will send you a message whenever there is any update to an event that the participant needs to know. Participants can reply the message to the event organizer as well.
Pro Recommendation list
Peatix comes with event recommendations where it recommends events based on your past order or your friends from Facebook who may be joining the event.
Cons
Con Lack of privacy
Messenger is owned by Facebook. Based on their privacy policy, this means that any information you provide (including messages sent) are used by Facebook to profile you and sell access to your data to advertisers.
Con Lack of end-to-end encryption
Secret (end-to-end encrypted) chats are only supported in one-to-one messages, and are not enabled by default, and the encryption has not been verified independently.
Con Ticket cannot be manually cancelled / withdrawn by participants
Peatix currently does not have the ability to cancel their ticket by participants and must be done through contacting the event organizer. This will become a problem when event organizers do not respond to participants messages through Peatix.
