SD-card without MBR

This probably applies to any Linux type OS, but I use Openwrt, let me ask here please.
What are the pros and cons of making and using file system (f2fs) on the SD-card (mmcblk0) without any partitioning? In my use case card is formatted on the installation and used within the system as additional storage, with removal on emergency case only.
Partition-less configuration seems to work smoothly. Looking through internet can't find any useful information on the subject.