"Why is there something rather than nothing?"
To my mind, the most important thing is the user experience. On my phone, Chrome is beautiful and smooth and fast, the tab management is weirdly fun, and the tab syncing is flawless. I care more about that stuff than I do about the size of the apk package.
I fail to understand your "all other" and "less than 5mb" only one browser that should actually be considered a browser is under 5mb.
Also the only real reason to care is caused by the lousy internet provided in this country, when you live in a country with 40mb broadband the difference between a 5mb browser and a 20mb browser in indiscernible by an actual human being.
All I'm getting at what is in Chrome that makes it so huge (btw, yesterday's update is 19.84MB)? When I see Android programs this size I think Kindle for Android: what is hiding in it?
Opera Mini and Dolphin Mini are a complete waste of time, if your going to replace the rubbish that come with the phone at least do it with a complete browser and not a washed out imitation. Skyfire is not even worthy of being counted as a browser, its barely a browser wanabe.
As for why its so big, who cares, it works, and very well. Only time I even think about giving a dam about file size is when I am not on wifi.
They broke it with the latest update, Chrome is set to default browser and now when I click on links it freezes on opening, I have to force close, then open Chrome manually and then click on the link.
Anyway, I still want to know why Chrome is so big.