Bots could be helpful to today’s life. Automation is useful to use. For example, we use bots to block spam, archive out dated threads. Bots make the platform programable, which extends the possibility of the platform. With bots, platform may have more functionality than it designed. Platform get benefits from content on it and the user traffic. Bots help both improve the quality of content, and may also attract more user traffic. And so it benefits the platform.
It is hard to blocking bots. Introducing more captcha could be a bad idea to stopping bots as it also harm experience of real people. And as we discussed before, attacker may still use more complex technology or even a real human (as discussed in 3.1) to bypass the restriction. So, disallowing all bots won’t help much if attackers may get benefits from their actions. But it also blocks friendly bots too.