Having it verified only solves half the issue(people lying). The bigger half is that people use this as a tool for 'bragging'. Joe Schmo making 90k in OKC isn't going to submit. Nor is the lady who feels severely underpaid even working for FAANG.
We cant let perfect be the enemy of better. Especially when dealing with a complex topic
The larger the dataset, the better. If you feel you're underpaid (lots of people are), you'll be able to know faster, and either negotiate for a bump or move on to someplace that values your skills at a higher comp rate.
Employers use information asymmetry to constrain their labor costs. Tools such as this help level the playing field.