cURL is awesome and we have a lot of cURL functions supported natively in FileMaker.
However, there are still functions, that is not supported.
Recently, I needed to be able to fetch emails from IMAPS server, but FileMaker's cURL implementation does not support that protocol.
With support for IMAP(S) via cURL, we would be able to interact with a mail server. Not that I want to build a full fledged mail server, but there are many uses for being able to fetch emails and process them in FileMaker.
It could be a helpdesk funktion, where users send emails with issues, where you want to track and organise them within FileMaker.
I am building a calendar module for several of our customers, where you can send calendar invitations. However, the way it is designed with the vCal standard, these files needs to be emailed. The same goes for responses from attendees. So in order to track these responses and update the calendar event, I need to fetch these email from an IMAP server. Most available plugins offers a lot more functionality, that is not needed here. So I want to go with cURL. But since IMAP(S) is not supported in FileMaker, I need to rely on a plugin.
In the same lane, we also need FileMaker to support SMTP(S) via cURL. This allows us to compose HTML emails and send via a STMP server. Currently, we need a plugin for that as well, even though you could do this with cURL.