The best thing about localizing an app - it can usually be done in a day, at an affordable price.
Erm... Yeah, maybe. And maybe not. If your app doesn't have much text, that may be possible, and it's better than nothing. But that's not the whole story.
Localization is -- as you have stated yourself -- a lot more than just translating. But it is even a lot more than the things you listed.
It starts at translating, and doing good, high quality translations already isn't something trivial (nor something you get for free). It continues with numbers and dates, and having to adjust the GUI because the length (and orientation, there is not just right-to-left in addition to left-to-right, but also top-down) of different languages differ greatly. Text that fits your screen in English may not fit (usually will not fit) in German.
And then, in case you have any kind of dynamically generated text (like "Do you want to trade %item% with %src% for %coins%"), the fun only begins. You will notice that not just the positions of the placeholders are different in different languages, and they obviously hold different words but they may also have a different spelling or be a completely different word depending on context (and depending on quantity). Some languages have e.g. non-optional ligatures which totally change a word depending on not immediately obvious conditions. There are even differences between e.g. localizing for "mainland" China or for "the rest of China" (same language but totally different writing system).
And then, you will notice that people who come from another culture behave totally different and have totally different expectations, and a different consumerism. For example, most people in Europe will sneer at grinding and at pay-to-win, and relatively few will pay to have a special-looking hat that doesn't do anything other than look special. In Asia, that's the most normal thing in the world.
You will find that (despite more and more people worldwide wanting "free") people in the US and in the EU are rather OK buying a monthly "all inclusive" subscription, but in China they will expect to pay per minute (and considerably less, too -- you cannot sell a software at the same price in countries with a currency that has only a fraction of the buying power). Different cultures will expect a vastly different graphical style as well. Furry characters or Korean-style cute stuff in Europe? Good luck selling these.
Different cultures regard certain "magical" numbers differently, too. Ever wonder why elevators in the US have no 13th floor? Ever wondered why all Chinese, rich and poor alike, will buy Lafite Rothschild, especially the 2008 at any price, no matter how unreasonable? (It's an OK wine, but most definitely not worth the price it's sold for).
After doing all the translations and stuff, you may realize that your very game design prominently makes use of the numbers 4 and 6 in some way. Well, good luck if you want to get sold in China. Could as well try selling a game prominently displaying "666" or "1313" to US soccer moms.
