2GB disk size

I've been using the Vagrant virtualbox images made here for a few months and I find them very useful, thank you!

I recently started running out of space while setting up my environment.

I guess that's because of the 2GB number here https://gitlab.archlinux.org/archlinux/arch-boxes/-/blob/master/build-inside-vm.sh#L7

To work around this, I tell vagrant to resize the "physical" disk in my Vagrantfile, and then I've done the following in my phase 1 provisioning script:

sudo bash -c "yes | pacman -S gptfdisk parted"

sudo sgdisk --resize-table=2 /dev/sda
sudo partprobe

sudo sgdisk -N 0 -t 0:8300 /dev/sda
sudo partprobe
sudo btrfs device add /dev/sda3 /
sudo btrfs filesystem balance /

but it would be nice to be 10 or 20 GB by default to avoid having to do this. Are the virtual disks dynamically allocated? What is the advantage of the number being so small?