I've seen yesterday this post on Google Cloud's blog:
This means that anyone can now obtain SSL certificates from Google Trust Services, and not just people who have signed up for the private beta. Asked via the GTS contact email if:
The service will be 100% free.
They have plans to support a full-ECDSA certificate chain (just like Let's Encrypt's E1 → ISRG Root X2).
Will post here when I have an answer from them. What do you think about this? Will anyone give it a try, now that it's in Public Beta?
I've also made this blog post explaining this release and how to configure it..
Update: I've received an answer to the email. Posted below.
IMHO, it is not worth trying due to Google's extensive history of abruptly discontinuing products that do not perform well enough for their own metrics.
Personally, I won't be using it because I avoid Google services whenever possible.
I have no great love for Google myself either, but I think more CAs using ACME is certainly a Good Thing, as it makes it easier to just switch to another CA if needed or desired. That is, if some does use Google, and then it gets discontinued, it should be fairly easy to just switch to some other CA (like Let's Encrypt, sure, but several others too).
I mainly use Google Trust Services when I want to have that extra compatibility of a cross-sign with GlobalSign Root CA (1998). But for most other things, LE is a more mature CA and has more features than GTS, like a full ECDSA chain.