We're mostly not, but our NCOA process is designed such that instead of just editing the current mailing address, old addresses are inactivated and then flagged using special contact point purposes to explain their history (either "NCOA Move" or "NCOA Delete"), with a third option ("Bad or Unknown") to be applied by staff when inactivating an address. Not a sanctioned use! But we are looking in to whether we have any applications for them, and if so, how to manage them.
We are not but are planning to start shortly with the Prospect2 integration.
We use both TNEW and Wordfly to manage purposes, and there is some manual usage as well. Unrelated: we had a header gif of a porpoise when someone has a specific purpose.
We did a mass update to migrate from types to purposes when they were introduced. We have used Wordfly for interests for similar, but our purposes are basically departmental (Dev, Tix etc).
One concern I have with Contact Point Purposes is what happens when a new primary contact point is added? There's no automatic mechanism to move purposes, and it's not clear that would always be desired.