While Grub is highly well-known, popular, sometimes innovative and of course very flexible, it is also more complicated than I would like and so I am not a user. The primary reason is because of its strategy to locate parts of the bootloader on the media in a way that can vary from one installation to another. The alternative, "standard" approach being to locate all parts of the bootloader in some pre-defined area, usually near the start of the "disk".
The Grub approach obviously has its justifications and advantages. Maybe some see the Grub approach as an advantage because e.g. if one accidentally loses access to an area near the start of the media where most bootloaders historically reside, then one can still potentially recover.
However, if understanding the boot process is a goal, I see the Grub approach as a disadvantage. It makes locating and verifying the bootloader more complex when it is fragmented into parts that are potentially scattered around the media instead of located in a pre-defined area near the start of the disk. If one makes changes such as the formatting or partitioning of the disk, are all the fragments from a prior Grub install accounted for? I would prefer not to have to consider that question. Whereas I know how to completely remove/reinstall the bootloader if I always know where it will be located.
If the goal is to understand the bootloader one is using on a lower level than simply using it, e.g., verifying it is there on the media, I think there are more simple alternatives than Grub.
Alas, last time I checked the Linux kernel is still not compliant with the "Multiboot Specification". This is unfortunate for me because the non-Grub alternative I prefer supports it and it really works well for multibooting. I would love to use it to try booting a Linux kernel. I suspect there is probably a workaround but making the easy choice to use Grub probably obstructs people from experimenting with alternatives.
While experimenting years ago, if I remember correctly, I booted a NetBSD kernel using the FreeBSD bootloader (the part written in Forth). I seem to remember this was possible because of compliance with the Multiboot Specification.
"One bootloader, many kernels." (Without chainloading.)