I know wildcards are useful and all, but they enable bad practices and increase risk. Now that LE makes it easy to mass-request certificates, excuses for using a wildcard are wearing thin. I'd rather LE never allowed them.

Wildcards allow me to serve all of my sub-domains over the same HTTP2 connection rather than causing the client to reconnect/renegotiate TLS/SSL.

This allows me to use domain sharding for those browsers still on HTTP 1.1, yet not have a performance penalty for doing so in the case of HTTP2.

Let's Encrypt does not support wildcard certs but they do support SAN certs, so if your list of subdomains is fixed then you can still benefit from socket reuse with HTTP/2.

Want so bad, but that said, I registred 6 subdomains at once, totally painless.

yes, would be very useful so I can use it with a private instance of ngrok

why? the signed cert is on your disk in 2 seconds. just request it on the fly. what's your use case for wildcard certs?

One usecase is a server that intercepts traffic for multiple domains. For example, a load balancer. I use AWS ELB/cloudfront for SSL termunation and they only except one cert, but they can send to multiple back ends. Then the server is routed on the host based on URL.

You may simply want AWS ELB to support SNI, and thus allow you to install multiple certificates.