Also worth mentioning that there is no official API for Reddit's chat feature. You have no choice but to use the website or official app if you're on mobile and want or need to use their chat.
Also the chat feature is extremely watered down and doesn't even have support for attaching images. But that doesn't matter if someone on Reddit chooses to contact you via chat and you want to respond. It compels you to use their platforms instead of a third-party client.
If you always use third-party clients or old.reddit.com you'll never even know that someone tried to contact you via chat, which makes it somewhat ineffective at getting people to stop using those.
Also the chat feature is extremely watered down and doesn't even have support for attaching images. But that doesn't matter if someone on Reddit chooses to contact you via chat and you want to respond. It compels you to use their platforms instead of a third-party client.