The Moon is tidally locked to the Earth, but the Earth is not tidally locked to the Moon.

I think if both were tidally locked to each other, such that one side of the Moon always faced one side of Earth, things would be less dynamic. You wouldn't have tides. Earth would be cooler because it wouldn't be flexing and squeezing and stretching from the Moon's shifting gravity (not sure if only a tiny bit or not).

I don't really know of a reason to make it so that it would be better for life on one side or the other of Earth.

The only related idea I can think of it that the Moon's far side has a thicker crust than the near side, which caused more lava flows on the near side. Maybe a similar thing could happen on Earth due to the Mars-sized object that hit the Earth to create the Moon where it knocks off a bunch of crust late in formation? It might not be scientifically possible, but sci-fi just needs to sound somewhat plausible.