In f2fs (Flash-Friendly Filesystem) what is heap-based allocation?

When creating a new Flash-Friendly Filesystem (f2fs) with mkfs.f2fs, there is a switch to turn on or off what is described as "heap-based allocation". The man page describes the switch as: > -a heap-based-allocation > > Specify 1 or 0 to enable/disable heap based block allocation policy. If the value is equal to 1, each of active log areas are initially assigned separately according to the whole volume size. The default value is 1. which, doesn't really specify what the feature does. Some searches suggest that this was changed from a default of on to a default of off (and suggested this was a "feature"), but there is very little I can find to describe what this option does and what the actual ramifications of having it on vs off are.