Is small talk a form of low-effort speech that should be discouraged?
And if so, how would you discourage it without being rude?
No. Even if it does nothing else, it signals politeness, affability, and adherence to accepted custom. If done well, it also makes your interlocutor more favorably inclined towards you -- in any case, it at least gives you the opportunity to make them more favorably inclined towards you.
Besides, you could make a friend.
I think NoHello [1] is one such example of speech optimization that may rule out some small talk. As for being rude everyone can be offended by something some people long for it so I stopped concerning myself with their afflictions and I just get things done.
[1] - https://nohello.net/en/
I'm curious to know what made you raise such a query.
It's why I don't want to be a, sales reps. I don't like small talk.
No, small talk serves an important social function.