Demilled projectiles, are they ok for bullseye or appropriate only for plinking?

Periodically i see advertisements for demilled projectiles at what appear to me to be reasonable prices.
Sometimes they even specify the make and model of the projectile such as Hornady XTP.

As always I appreciate your thoughts and experience.

It all depends on how the bullets were pulled and subsequently handled. Do your due diligence on inspections both visual and measurements then load a test batch, testing in a pistol of known accuracy with a Ransom Rest if possible. Personally, I would practice with them and shoot matches with new bullets.