Door lock gasket

[sanders7981]

I installed the door lock cylinders last night gaskets are kind of bugging me.  They are grey, and contrast against the Big Bad Orange paint color.  Are they necessary?  They seem a bit large for the lock cylinders, and one would think the lock retainer would pull it tight enough to keep water out.  Any suggestions to keep from having to use them?  Any other sealer suggestions?

[Lennard]

You can use gasket sealer out of a pressurized can with a dispenser tube( hope you get the picture) and wipe off the excess sealer.