It's just a humidifier tank, use distilled water and keep a filter on the PAP device, it won't need a regular cleaning. I've had three tanks (sealed) total for my Fischer Paykel device that I've had for 20 years but the first two were somewhat fouled by occasional use of tap water. You do what you must.
I've an S8 Elite CPAP with humidifier for five years and it's just fine with the original tank. Pristine.
Four stars for build quality, but I'll be buying the dishwasher safe version for a replacement, just so I can use reverse osmosis water that isn't as mineral free as supermarket distilled water. If I need to.