What it does: The old settings in the config file for 1.12.2 and 1.7.10 could be ported to 1.16.5. Things like controlling spawn rate, biome blacklist and whitelist for mob spawning, dimension blacklist and whitelist for the Tardis and others. "tardisMinY" is the only option in the server config file (correct me if I am wrong or I need to do something in order to get the other options).

How it benefits: The player can then have more control over what happens in the mod. The config file can also help the player see intuitively what features the mod has: if it is in the config file, then it certainly exists.

Why it would be cool: You could turn down the spawn rate of the mod's mobs or increase it if is too low. You could also live in a Savanna or Desert biome and still be assaulted by hordes of daleks from everywhere, not just very rarely from around the river nearby. :)

this would be a less head ache if this was added and actually change some things