Limitations

Many "decoding" tools are wrappers for malware. They may return a partially functional script while embedding a backdoor in your server.

What impressed me most:

IonCube is a PHP encoding and encryption tool that helps protect PHP code from unauthorized access, modification, or theft. Developed by IonCube Ltd., the software has been a popular choice among PHP developers and web hosting companies for ensuring the security and integrity of PHP applications. IonCube achieves this by converting PHP code into a proprietary, encoded format that can only be executed by a compatible loader.

(where encryption keys are generated at runtime), reliable decoders are rare and often unreliable. NEW Release - ionCube Encoder 13 with PHP 8.2 support