I too have been in the sleeve or not camp. I think I mentioned on the page I linked to that I used to like the feel of the cards, but then with a current trend of sleeving I thought I would try it out.
I think the point is that your cards will last longer and accidental spills or greasy fingers won't be such a problem. There is also less friction between the cards, resulting in less wear. The biggest benefit is that the cards will look new, so mixing in cards does not look so obvious. Putting a pristine Blood Moon set in with a well-used base game with show you what I mean.
I have tried most of the makes on the page, and even though I settled for Mayday sleeves the other month, I have yet again changed my mind! (I can sense yet another "What was the last card I sleeved? competition"!!)
I have now de-sleeved my cards and am awaiting a delivery of FFG sleeves. I think the thickness of FFG's sleeves gives them a great feel, and in comparison the Mayday ones are really flimsy (though they do offer a thicker "premium" version). Arcane Tinman sleeves would have been a good second choice as they are 80 microns thick. It's still a balancing act of quality over quantity though as you get twice as many thinner sleeves for your money (more with Swan Panasia sleeves). Just go with whichever you are happiest with.
The only problem you might have it from stacking the newly sleeved deck as it will be somewhat larger than before, but you can easily split it up into manageable chunks.