If you have caps that are not poly cone, you will want to use silicone tape to seal off the caps (Out of paranoia, I used it even with the poly cone caps)
From my understanding, the reason for getting the caps with the polycone liner (versus the ones with no polycone liner) is because the cone itself displaces air that's trapped in the bottle...as it's screwed on to the bottle. That's particularly important since we're storing nic base in them that is affected by air trapped in the bottle. For most other liquids stored in glass bottles...other types of caps work equally well.
The actual seal of that particular type of cap isn't better or worse than the caps with a flat foam liner or other material in them.