What is the benefit of using this when a local, unlimited-use library without latency issues can be used?
A lot of these seem useful and having APIs that need to be updated is a good VP, however for things like HTML to PDF, there are libraries that already do this.
People will likely use the HTML -> PDF API, but in terms of the new APIs you are developing, I think you will attract more customers with things that cannot be implemented simply with a library and instead need to be managed by you.
Just my two cents, good luck!