You can get away with not useing the sealer, but as has already been said, there will come a time...
The sealer is there as an insurance when the gasket goes round angular faces.
You have to remember that the heads are not precision machined, they are just skimmed flat to a known good tolerance that is all.
Now if the cam cover is also made to same tolerance there's no guarantee that all surfaces will mate as per the CAD model now is there!
The idea of the sealant is that it takes up any deviation when the seal does not sit on a flat surface or goes around a radius, that way you know for certain that you have a contact on those tight male and female angles. In an ideal world you'd have everything machined to within 0.01mm and the seals would be .2 or .5 oversize, but this isn't racecars, it's production cars, and in the grand scheme of things, it probably saved .5p per seal if it wasn't any bigger than what was required to do the job.
Also remember that the rear of the engine is also a pig to get to, and difficult to check to see you have proper mates of all the surfaces.
So please... with a cherry on top... use the sealant!
Why not buy the Cam cover gasket kit from the OOF shop? - it contains all that you need, and a tube of sealant - and weighs in very cheap considering that you don't have to deal with knuckle draggers
