Difference in dmg numbers

This is a total noob question. What exactly is the difference between a weapon that has, for example, 50 dmg vs. 25x2 dmg?

If there is no difference, why do it?
But if there is, please explain this to me.

I’ve wondered about this for years. Other game do it too.

25x2 means that it’s firing 2 projectiles (or beams in the case of Laser weapons) that do 25 dmg each.

That makes sense. Thanks.