For me it depends on how much you can afford on wages for the position.
I think their benefit comes from field position from good kickoffs/punts rather than scoring, as all extra points are good and being in the right position for field goals is random. BPOS seems to be more important than skills, so 3.5* talent minimum.

There's a school of thought that kicking/punting skill is irrelevant once it gets to 12 and over. There's also a school of thought that says it is not a position worth wasting 4.5* talent players over.

From my point of view, I just had this player whose speed and strength capped quite low, and I trained him in both kicking and punting (as well as agility, vision and footwork so his wages didn't go out of control).

I'm also considering letting another player with naturally good kicking and punting play that position in friendly matches, so I have a reserve with good BPOS ready to step in should the good one get injured.

There are far more important positions on your roster though.