Explanation is still the same: it won't become official until someone makes good enough test program (that automatically fills the partition and does all kinds of file accesses and also checksums each file). Only if it survives multi-hour testing of this kind: it can be considered safe
Max partition limit is already about 1.6T. There are 4 "limits": original ~5G (1k "smalldisk"), original ~104G (1k), new 411G (2k) and 1.6T (4k). Internal index block size doubles each time max size increases.