I always see people buying frenzies and sheriff when they have near max money to compliment their rifles. But ghost and classic are objectively better for this reason that I've never seen anyone else mention: both classic + ghost have a 0.25 second quicker equip time than sheriff or frenzy.

When you run out of bullets and desperately need some damage before you wait for a reload is the only time you switch to your pistol. That 0.25 seconds is extremely important in that narrow situation, which is the only situation that matters anyway. If I have a ghost, I can equip it and get 2 shots off before you can get 1 shot off with your sheriff or frenzy...

tldr; consider the equip time of your side-arm next time you are buying a pistol as a secondary emergency weapoon.