Low cost devices can have limited storage space -- when it's 64GB or less Microsoft recommends WimBoot, though there are probably devices out there using WimBoot with drives >64GB too. It is not a requirement however, & devices with the minimum 16GB are sold that do not use it. The advantage is that with a ~4GB .wim file, you can have a complete Windows install taking up less than 4GB on the Windows partition.
With WimBoot what you do is put a compressed Windows Image file [.wim] on the Recovery partition. A .wim file can hold anything from Windows setup files to a complete Windows image with additional software. According to Microsoft docs re: WimBoot, you should install Windows with the necessary drivers on the target device, then create the .wim file from that. Following Microsoft's directions, using tools they developed for this process, you 1) make the .wim file smaller, & 2) map links from the Windows partition to the actual files/folders in the compressed .wim on that Recovery partition.
Microsoft may limit the updates that are shown or offered when you use WimBoot. And since the Windows install depends on the .wim on the Recovery partition, you can't off-load it to a USB stick & use that disk space. Anything not stored in that .wim is not restored when/if you use Windows Recovery, though it appears Recovery *might* be customized to automatically download & run whatever. Being that it's not an actual set of individual files on the Windows partition, altering those files rather than re-creating that .wim is problematic -- a prominent Gotcha for lots of people who were [are] planning on upgrading to win10. It is doable, but more work & more involved than simply upgrading Windows or installing a fresh copy.
How do you tell if your hardware uses WimBoot? Easy -- checking the Windows partition disk space in Properties, the figures you see will not agree [won't come close] to what's displayed in the properties for the Windows folder, e.g. you might see only 3-4GB used on that entire partition, yet Windows Properties might show that folder using more than 4 times that amount.
Another problem that's more common with Windows Tablets is that Windows might be 32 bit, yet the device uses UEFI to boot. 32 bit UEFI is rare enough [outside tablets] that most boot discs/USB sticks won't work with it, including those created by backups apps from Paragon, EaseUS, AOMEI etc. Macrium Reflect Free will work. Restoring that disk backup image to a VHD, you'll need a partition app to assign a drive letter, making the Recovery Partition contents accessible/visible.