Interesting. Perhaps the error I received at the time was worded poorly giving me the impression there was a cost. Thank-you for the clarification. For now I will stick with LE as I do not have to create an account but I will keep ZeroSSL in mind should LE change things up.

[Edit] I remember now what led me to this conclusion. The error said I needed an account. I looked at the pricing page which indicated I had to pay for wildcards so I immediately looked for the flag to change back to LE. Looking at the pricing page I would still reach this conclusion. There should be some text that makes it obvious that using ACME allows for free wildcards.