This has bothered me for a long time. I love it when WHMCS introduces new features, but trying to implement some of it is often a challenge.
Why is there no built in support for multi-language support unless you're trying to build an "addon" module?
Basically any other type of module can output code to the client area, and it makes no sense that you have to write your own code to support multi-language. I mean, the code already exists in WHMCS 😅
The documentation is lacking a lot of information. Take this as an example: https://developers.whmcs.com/provisioning-modules/supported-functions/. There are some functions (like _AdminArea) that just has no information at all.
How is it used? You can't echo or return anything. Is it just a typo and meant to say _AdminLink? I know how to use that function by looking at other modules, but there's still no documentation about it.
Why is there no documentation for Application Links? It's a really cool feature, but it makes no sense that the feature is basically reserved for cPanel.
Another nice feature that feels like it was only built for cPanel is Server Sync - mostly because of this: https://docs.whmcs.com/Servers#Sync_Report
... But some control panels do. I know that cPanel doesn't. Some other control panels (not just limited to web hosting) do keep a record of the user's full name, address, phone number etc.
Importing a client into WHMCS using the Server Sync feature feels so akward. Who wants to send an email to their customer that starts with "Dear Name Placeholder"? That's very unprofessional.
I know that not all control panels track the client's details, but who thought it would be a good idea to not even implement importing the details in case the control panel actually did? It would make life so much easier for WHMCS admins wanting to import clients.
I hope someone can give me an explanation that isn't "Because WHMCS just doesn't care" 😅