> It's Linux under the hood which will always make use of more memory,
Linux won't really be the beneficiary of all the extra RAM in this case. The motivation behind the extra RAM is Java.
It is well known (i.e. researched) that garbage collection system performance is heavily dependent on free RAM. You typically want around 4x the amount of your peak memory usage to keep the garbage collector speed reasonable. The more free RAM, the better the performance.
http://sealedabstract.com/wp-content/uploads/2013/05/Screen-...
But having 4x has been a real challenge for mobile and Android over the years, especially as people want to do more and more with the phones. It also didn't help that Dalvik and ART are new ground-up implementations of the Java VM which means a lot of optimizations for garbage collection needed to be reimplemented from scratch.
The lack of needing to support a garbage collector is a big reason Apple can get away with shipping far less RAM in their phones which in turn helps keep their profit margins high.