This might make sense, if all of your users are located near your web servers and you can comfortably handle the load of all the requests hitting your web servers.
If the user making the request is in Australia, for example, and your web server is in the US, the user is going to be able to complete many round trip requests to the local CDN pop in Australia in the time it takes to make a single request to your server in the US.
Latency is one of the main reasons TO use a CDN. A CDN's entire business model depends on making sure they have reliable and low latency connections to end users. They peer with multiple providers in multiple regions, to make sure links aren't congested and requests are routed efficiently.
Unless you are going to run datacenters all around the world, you aren't going to beat a CDN in latency.
If the only thing you have on the CDN is libraries, it's faster to have your site host them even if it's on the other side of the world. When HTTP2 file push is widely supported, it becomes even more in favor of hosting locally, as you can start sending your libraries right after you are done sending the initial page without waiting for the browser to request them.
If you are using a CDN for images/video, then yes, you would have savings from using a CDN since your users will have to nail up a connection to your CDN anyways.
Then again a fair number of the users for the site I'm currently working on have high latency connections (800ms+), so it might be distorting my view somewhat.
If the user making the request is in Australia, for example, and your web server is in the US, the user is going to be able to complete many round trip requests to the local CDN pop in Australia in the time it takes to make a single request to your server in the US.
Latency is one of the main reasons TO use a CDN. A CDN's entire business model depends on making sure they have reliable and low latency connections to end users. They peer with multiple providers in multiple regions, to make sure links aren't congested and requests are routed efficiently.
Unless you are going to run datacenters all around the world, you aren't going to beat a CDN in latency.