Does QRZ 50 states award qualify for ARRL WAS award?

No - LoTW does not directly recognize QRZ as a source of confirmations (nor does QRZ directly recognize LoTW without intervening export/import steps)

If you up your subscription level, you could then export your QRZ log in ADI format, then use ARRL TQSL to "Sign and Upload" to LoTW... you'd very likely get a ton of confirmations to line up. Maybe not all 50 states (only those users who also use LoTW would confirm on LoTW).

But as a "Ham Member" you don't have the ability to export QRZ Logbook ADI files. That's a perq of paid membership.

The XML membership level (and above) would give you this functionality:

https://ssl.qrz.com/products/

Dave
W7UUU

Note: ARRL does not require such but will accept "written confirmations" via paper QSL cards as verified in person with ARRL "Card Checker volunteers" but the VAST MAJORITY of confirmations are via LoTW and 100% electronic. Probably less than 2% of all W.A.S. awards are submitted by "written confirmations". I have no idea where you would have read that ARRL requires written confirmations - prior to LoTW sure - but that's well over 20 years ago.