In some other StackExchange networks, I am currently in, for example in Mathematics and Chemistry, I am able to post questions successively only after a delay of 40 minutes. But here on Space Exploration, I am able to post within 10 minutes, and this is really helpful as I don't need to wait till I post the next question. What is the reason for this? Or equivalently, why is this present on other sites of this network?
On sites with a larger volume of users, spamming is a bigger issue, so rate limiting is a helpful tool to ease the load of community moderation. We don't have a problem with the moderation load here.