If "close enough" works, then it's nice to have the skill. Having the skill requires occasionally using it.

Where accuracy is important, since we almost always have a calculator with us now, that's a no-brainer.

Maybe more to the point, though, understanding how percentages work is wise. It's one of the few arithmetic topics that we encounter regularly in life.

In this case, 23% of 53 and 53% of 23 each have their own little trick, depending whether you'd rather overestimate a little with 1/4 of 52 or underestimate a little with half of 24. I find it handy to be able to think that way, especially for example when trying to get out of a taxi and paying cash.