You asked if it was worth $80. $80 therefore has a value to you that you suspect is similar to the difference between these two guns. That's what that question means.
If you think the upgrade might not be worth $80, then even though you think the longer slide is an advantage, you might not get it because $80 is more valuable to you than that advantage.
If you care about $80 on a pistol, don't get a .45, unless you're not really going to shoot it. If you're not going to shoot it, don't treat it like a SHTF item because that's not what it is. It's a toy you don't really use.