TS also has a PM system, and Discord isn't very good to use as just a web app, so it'd be better to download.
The perm system on TS is pretty broken/super limited at the moment for whatever reason, but I still much prefer it to Discord. The interface is just too much better than discord with the channels.
If TeamSpeak is what's stopping you from applying for staff then I don't know what to say. Outside of parental issues (why would you have Skype ???), there's really no reason I can see to not have it even though not many people use it actively on Meep.