Disk Utility is an inbuilt utility of Mac that provides various useful features for better management of your data and partitions. Along with various other features, this utility of Mac allows its users to resize an existing volume without encountering data loss, but with some limitations. You can decrease the size of any volume with 'Disk Utility' of your machine, but you can increase the size of a volume only when there is sufficient free space available between the volume you want to expand and the next partition on your hard drive.
You can see this scenario practically as, when you want to increase the size of a volume, you have to delete the partition that is below this volume. This certainly causes data loss (if you do not have the backup of the data on this deleted volume). However, data loss will not occur on the volume that you wish to expand, it only occurs on the partition next to it.
On the other hand, if you use Stellar Partition Manager software, then you need not worry about the availability of free space just below the volume that you want to expand. This is because of the fact that the software recognizes all the free space available on the hard drive, adjusts it, and hence makes this process secure and free from data loss. This is the biggest advantage of Partition Manager software over Mac's inbuilt 'Disk Utility' to resize an existing partition.
Apart from this, you can undo your last selection to perform an action for which you do not want to proceed further. Moreover, you can hide a partition with this professional utility for Mac and reveal this volume easily whenever you want.