It is in the public interest to open access to the basic data attributes like property address, purchase price and date. This is not considered private. I understand that things like number of bedrooms, roof materials etc are all value-added columns which makes this a product which can be sold.
I am surprised to see WA Government sells this data. It goes against the Freedom of Information Act Freedom of Information - Landgate .
For reference, NSW released this for free about a year ago - https://valuation.property.nsw.gov.au/embed/propertySalesInformation
Again, this is only for public data owned by WA government. Not about valuation, not about value added data, but only the address, purchase price and date.