Why mono?

I just installed a Lyra Helikon mono on a spare armwand for a Graham 2.2 The sound is really present compared to mono recordings on my stereo cart (Benz LP) with the preamp switched to mono.
I have been thinking about why. The best I can come up with is that there are phase errors in the mechanical process of pick-up from the groove, and that these are eliminated - or greatly reduced - by the geometry of the mono coil vs. the stereo coil(s) in the cart. Less degrees of freedom, less error.

Hello everybody! I'm curious as to your speaker systems? Are you using a single speaker for true mono playback? Or are you listening to your stereo system as two channel mono? I have been listening to two channel mono and have found it to be questionable. When I sit in the stereo sweet spot I hear a bump in the lower mids. And when I sit elsewhere I hear odd phase issues that I attribute to timing errors. And the low freq is cancelled. Thoughts?

Many modern mono carts have vertical compliance and will Not tear up a stereo record. The Denon 102 is such, and has been out for years. It has two long output pins to hook up your stereo leads (doubled up). The AT 33MONO and MONO3 are inexpensive MC and HOMC if you want to try a relatively inexpensive mono cart w/vert cu. The 33 has 30dB of vertical rejection. All of these have spherical tips between .6 to .7 mil for the 102.

A mono switch is not the same as using a mono cart. Vertical information does not get cancelled, it gets blended. That's why you might get dramatic noise reduction with a beat up mono pressing. It can be startling.
A stereo cart has channel imbalance and phase difference. Things like skating, azimuth, alignment will add to the difference and sound blurry or fuzzy. A mono cart is relatively immune to these differences (depending on vertical rejection) because there is only one output.

Many mono carts have vertical compliance. If you're unsure about a pressing you won't have to worry about destroying your record.
For a more complete explanation:
http://ortofon.com/hifi/products/mono-series