Thought the same thing until my inspector showed me hairline cracks in ours. Water got in over a winter and wrecked a chunk of the flue lining. Fixing that was way more than a simple crown repair would've been.
Hey, isn't water damage from cracks the main reason they even suggest caps? I read an article a while back that said it's not just about rain, but that freeze-thaw cycle in winter that makes tiny cracks way worse. It basically said skipping the cap is like gambling on your masonry not having any weak spots at all.
Wait, the flue lining got wrecked? That's a whole different level of bad. @the_linda might call it a gamble, but that sounds like losing the whole pot.