Namecheap PositiveSSL | Web Hosting Talk

I've been looking for a new basic SSL certificate, and the $ 9 / year PositiveSSL certificate from Namecheap looks great, I'm not even sure why we paid $ 70 / year for a very basic GoDaddy certificate.

One thing that keeps popping up about PositiveSSL is that "it's for low volume sites, like personal blogs, etc." Can anyone explain this? What does a certificate have to do with the traffic volume of a site?

Also for my life, I can not understand what is the difference between PositiveSSL and the $ 19 / year "EssentialSSL".

I have not been able to find answers to these in the network. Thank you!

PS: it is quite ironic that at present, WebHostingTalk is not safe.