Does the choice to stay or go make a difference

After experimenting with my own weapons, I can confirm that these represent how many moves are in a Light or Heavy combo with that weapon.

That is, if you have a weapon as your Primary with Lt 3 Hv 2, you will do a 3-hit combo with your Light attack button. If you have this weapon as your Secondary (Heavy) weapon, you will do a 2-hit combo with your Heavy attack button.

Ah, the big choice.

Since the ending sequence is nigh impossible without accepting help (this is clearly intentional, as the entire point is that you can't take on enormous tasks alone), you accepted it, right? Every person that assisted you was actually someone who chose to erase all of their save data for this purpose. Had you chose to delete your save, someone out there who needed help on the ending sequence would have gotten assistance from you.

I originally declined in order to 100% the game, but as soon as I had done so, I went back and redid this sequence so that I, too,

could erase all save data in order to assist someone else.

If you choose yes, you will actually be prompted for confirmation about 7 or 8 times before it actually happens.

During the sequence directly following, it will show all of your data being deleted, one item at a time (though many are skipped over so this doesn't take an eternity). The very last part shows all of your save slots being erased. This means you cannot simply copy your save data to a second save data slot. All three are erased entirely. The only record of you having played the game and made this choice is that you will get an alternate background for the title screen. It looks like this: