Possibly unrelated and yet possibly informative:
I had a couple of EZ fills them which both stopped working correctly within a year, they got stuck partially open after use. Sent them to someone for repair who told me that there were mineral deposits within the valve which prevented it from closing correctly, and that it indicated that I hadn't been correctly drying the air I was putting into my tanks. I've had several HPA compressors since getting an imported 3500psi Axor compressor back in the 1990s. I'd never bothered to add a separate air drying mechanism stage with any of them and never had any mechanical problems related to moisture.
Nonetheless, the problems with the EZ fills convinced me to get an Alpha Inline Moisture Filter to use with my compressor.
It seemed expensive at the time at ~$400 US but the overall design is excellent. It includes a pressure gauge and pressure release valve for the drying column, and one-way pressure control valves on the column which keep it under pressure when the compressor is turned off. That last one is a useful feature which allows the hose between the compressor and drying column to be depressurized while maintaining pressure within the drying column itself. It would have cost me that much to piece together the same thing from separate parts and I wouldn't have done as good a job.
I view an investment in a specialty HPA air drying device like this to be an insurance policy which reduces the chance for unexpected water damage to my airguns. I never got one back in the day because I couldn't afford it and nothing before the EZ fill valves ever broke as a result.
JP