When it comes to climbing socks climbers split in two groups. 

There are the climbers who swear on climbing barefoot (with climbing shoes) because you apparently get a much better feeling. To be fair in Fontainebleau we have seen a lot of people climbe completely barefoot so.....

And theres the climbers who always wear socks and claim that there is no difference in performance, you get in the shoes easier and where they're definitely right, the smell of the shoes is not nearly as bad as if you'd climb barefoot. 

The third "group" op climbers are those who buy there climbing shoe and initially climb without socks, and only if the shoe becomes too comfortable over time due to wear and tear they put on socks and this causes the shoe to tighten again.