The hibernate and page files are low level system files. Both are used to temporarily store system memory (RAM) on non-volatile storage (disk or ssd).
Hibernation—also called suspend to disk—is powering down a computer while retaining its state (so, for example, word processor files being worked on don't have to be saved first). When the system is powered on again, the RAM image data is restored from the "hibernate image and the system proceeds as though it had not been powered down at all.
Paging is a central characteristic of virtual memory systems where each program is given the illusion that its process-specific memory space is all of the address space on the computer. That illusion is provided by moving not-recently-used small blocks (commonly 4,096 bytes, but sometimes larger—32 KiB, 1 MiB, 16 MiB, 1 TiB) of memory to disk until needed. When a program accesses memory which has been paged out, a low level CPU operation called a "page fault" is attended to by the o/s kernel to bring the page back into memory and then resumes the program seamlessly at the faulting instruction so it can execute as though the page had been in memory all along.
Both paging and hibernation are implemented at the lowest levels of the operating system. As a result, it is inconvenient and messy for a disk defragmenter to cleanly move the disk blocks of those files around while they are potentially in use. To greatly simplify programs which might do that, it is easier to recognize these files and prohibit such operations.