The mono reissues are cut with a stereo cutter, so can play those with a stereo or a modern mono cartridge. Modern mono cartridge means, the stylus is identical to their stereo brother but you will have a much better performance. Less noise and that is the real advantage, the tones have colors which are hidden when using a stereo cartridge or a mono button on the preamp. The difference is not day and night - based on the stereo cutting process with a mono signal - but there is a clear difference. The mono button for example kills every life and is very boring to listen to.
A different chapter is old mono (no reissues). Here you have to go for a mono cartridge.
A different chapter is old mono (no reissues). Here you have to go for a mono cartridge.