[DelTaco]

To be fair, I've downloaded Messenger like 6 times this year because they prevent you from using the messaging capabilities of Facebook in a mobile browser - even if you request the desktop site.

So sometimes I'll have to download it when I don't have access to a desktop, send or read a message I needed to, and then uninstall it.

[durzagott]

You can use mbasic.facebook.com to see an low-bandwith version of Facebook. From there you can view and reply to messages without having to install the Messenger app.