So, when you have an operation and they wind up performing a sex reassignment surgery instead of an appendectomy due to the lack of atomicity, consistency, isolation and durability in their database, you would be OK with it?
Demagogy. Your example has nothing to do with ACID. Such a case would inditate wrong data entry or a client software bug.
By the way, such errors do occur. Even in systems where the database is ACID.
I have not read the article, but I guess they store either very frequent data (measurements) in NoSQL, or large data (3D images). Depending on nonfunctional requirements, neither is possible at all, or cost-effective with RDBMS.
Again we could get infinite scalability with Cassandra for free.
No, no, it is the Apacha Foundation.
I believe you make my point stronger by showing that even with such small resources and incompetent developers, it was possible to create the most moddable game (ever?). Without actually putting any effort into moddability... That made it possible to spend all of their limited resources on a good game design. That is not a small feat.
I worked in both C and Java for many years, and regarding moddability, no, it is not possible to beat Java using C with equal resources. My son's code regurly replace builtin Minecraft classes, runtime, without a significant effort, if the existing extension system does not provides (yet) the necessary hooks for him.
What we would indeed need, is the multi-datacenter capability. Which you get for free with Cassandra... We also sorely needed performance a few years ago (15k SAS drives was slow after an internet hiccup for example), but SSD drives helped in that. Again we could get infinite scalability with Cassandra for free.
You must choose in such a situation: either the - only theoretically needed - ACID, or the actually performing and highly available NoSQL with its additional operations, coding burden?
I only have a little experience with Cassandra, but I can tell you, that consistency is very easily tuneable in it and it is also provides durability. Atomicity is restricted (AFAIK you can get atomicity if all your data goes onto a single data partition). Isolation does not exist.
I believe that it is very easy to say that something need ACID, while actually most data does not require ACID. They can, and as I read the article they do use relational database for those data which actually require ACID. NoSQL does not mean that you are in a constant state of getting garbage from your database. And yes, RDBMS are not failsafe either, if nothing else there are coding errors in the applications which use them.
I think one of the things which made Minecraft popular is Java. There are a huge number of plugins and mods, these wouldn't happen without Java. It is easy to reverse engineer and modify anything in Minecraft exactly because it is in Java. Even its plugin system was written by an external developer! I do not really know Minecraft myself, but my 13 old years son plays Minecraft, and he spent months coding Minecraft extensions, and as far as I hear from him, a usual server uses a very large number of extensions.
Java is not ideal for graphics intensive applications, but it is also not that bad either. Minecraft (without mods) does not represent what is possible in Java, becuase it is very under-optimized. The new 1.8 version is much faster, but there is still much room for optimization.
This is similar to why PHP web softwares are very popular, they are not perfect, but they are very easy to be modified.