I have not used sealer. I did have an issue with printing the inserts and such on my HP; they were really smudgy, so I ditched it and use a Canon to print everything. No more problems. Plus, it has been my experience that the heat from the player will “cure” the disc label…
I have trade that these sprays can keep the ink from smudging if and when they get wet and fading over time. But I didn’t know if the new disc printers and printable discs were more reliable in this aspect or not