The developers of WinEdt have kept the unregistered version functional (with nag screens) so that users do not lose access to their work. This "honor system" relies on users supporting the development of the software.
If you are a student or work in academia, WinEdt is quite affordable compared to other professional software: winedt 11 registration key free
If you cannot afford a WinEdt license, you do not need to resort to piracy. You have excellent, legal options: The developers of WinEdt have kept the unregistered