For simpler applications, 32 bit will use less RAM without any noticeable disadvantages, so it's not the worst default in the world. Kind of questionable, perhaps. It does mean your software will work on older PCs, though!
It also depends how you write your code because there are many ways to reduce memory usage, for example switching to arrays and 32bit indexes instead of using native sized pointers. Can also use smaller data types than size_t etc.
Having both x64 and x86 as configurations by default is a step forward, but realistically I wouldn't want any configuration in my solution which does not work and is not supported.