[ish64mmm]

When I was younger I taught myself PHP so I could code Minecraft Bedrock Server Plugins, as funny as that seems trying to find some usefulness into this coding language?
Is there a purpose for PHP? What is it used for? 
Looking for something interesting to use this acquired skillset in!

[Refurbish1416]

You can do pretty much anything in PHP, but it's not going to be the best option for everything. PHP is the most useful in building websites like this forum or doing web related work.
Your knowledge of PHP can jump-start your learning of other programming languages. My advice is to find out what you want to build first, find the best tool to build it, then learn that tool by building your project.

Please do not limit yourself to what you already know and try finding a project that suits your interests, skills and needs.