You are right and I would add that this is even a privacy and security measure, to make use of wildcard certificates. The reason is, those subdomains will be public because of websites like crt.sh which show all subdomains which have their dedicated certificate. Obfuscation can be helpful in not disclosing which are some services or naming schemes you use for yourself even if it is only meant to be for internal use.
Obfuscation can be helpful in not disclosing which are some services or naming schemes
The "obfuscation" benefits of wildcard certificates are very limited (public DNS records can still easily be found with tools such as sublist3r), and they're definitely a security liability (get the private key of the cert stolen from a single server -> TLS potentially compromised on all your servers using the wildcard cert)
One of the risks associated with wildcard SSL certificates is the increased attack surface they introduce. If one subdomain becomes compromised, it opens the door for potential attackers to gain unauthorized access to all subdomains secured under the wildcard certificate.
(first google link)
The advantage of wildcard certificates is that you don't have to expose each single subdomain over internet. Which is great if you want to have https on local only subdomains.
If you still use HTTP for cert verification on ACME, you are doing it wrong. Use DNS-01 only, there is no need to allow any inbound traffic to your servers. and HTTP will not give you wildcard anyway.
Yes, you are right, I already use DNS validation. But it is just it is easier to request a single wildcard certificate for my domain and have all the subdomains that I use for the local services defined only in my local DNS.
I cannot fully automate the certificate renewal because namecheap requires to allowlist the IP that can call its API, and my ip is dynamic. So renewing a single certificate saves me time.
Also, the wildcard certificate is installed on a single machine, so it is not the I increase a lot the attack surface by not having different certificates for each virtual host.