Let's say you host your site on your own server at www.example.com. You want that to be served by HTTPS. You also have a subdomain cdn.example.com for static assets which is CNAME'd to a proper CDN that you want to use HTTPS with also.
With a wildcard cert, the third-party CDN would need your private key for your self-hosted www.example.com site. With different keys & certs per-site, the process is more modular.
I agree that wildcard certs would be great and I'll default to using them for the simplicity (e.g. temporarily activate a quick test.example.com site to check something works) but the ability to keep things modular is also great.
With a wildcard cert, the third-party CDN would need your private key for your self-hosted www.example.com site. With different keys & certs per-site, the process is more modular.
I agree that wildcard certs would be great and I'll default to using them for the simplicity (e.g. temporarily activate a quick test.example.com site to check something works) but the ability to keep things modular is also great.