new oil filter smearing?

It seems to be common advise,is to smear oil on the new filter seal. Does it serve a real purpose?

Yes. It helps the new filter seal and it also lets the new seal glide on the surface so it doesn't bind and possibly tear it. It's no different than lubing an oring or any other seal.

Thank you gents... I'm a hobbyist mechanic and sometimes I bother to do it, and sometimes I don't

Yes, it helps the rubber seal better on the block. and ALWAYS check that the old O-Ring came off, unless you want an oil shower