The bottom part of the monitor of iMac Late 2012

On my desk where I use my iMac on, I have another small desk over the keyboard I use so I can put stuff on. And I usually put the bottom of the monitor of my iMac on that small desk to make it closer to me. The width of that desk is more than the width of the monitor of my iMac. And the surface of that desk kind of completely (not 100% because I have a wood board beneath my iMac stand so there's a tiny space (like 2mm) between my iMac and the small desk) blocks the bottom of the monitor of my iMac, where there are thin, long holes. Will this affect the longevity or performance of my iMac at all? The glass screen is warm (kinda hot around the bottom) and the back of the monitor is a bit warm too around the center, but the other aluminum parts are not warm. I don't hear any loud fan noise.

The holes I'm talking about are these. https://cdn.arstechnica.net/wp-content/uploads/2012/12/imac-speaker.jpg