So much complaining. The web app version is crap, of course they want to move people over to the app. Why waste resources on an inferior web version when they can focus their attention on the very successful mobile app. Its just good business sense and seeing that 99.9999999999% of Facebook users already have Messenger installed, its a non issue.
* It takes up zero phone memory. Yes, this is still an issue on really cheap Android phones. [0]
* It takes up zero phone resources, unlike the Facebook app, which is known for slowing down your entire phone. [1]
* The messenger app wants to send me notifications about stupid things and collect personal data using its over-broad permissions. I don't trust Facebook, and I'm not a tinfoil hat type.
* I don't want another chat ecosystem in my life, but if someone does message me on Facebook, I'd like to be able to see it on my phone without having to install an idiotic, resource-sapping, spyware app.
I really, really don't want a "good" Facebook chat solution. People want to chat with me, they can use Skype, Google Hangouts, or Slack. Or just send me an email and we can talk on the phone.
[0] http://www.gsmarena.com/samsung_galaxy_core_prime-6716.php