The viewers have a point, certainly (4)
I believe the answer is:
eyes
'the viewers' is the definition.
'a point certainly' is the wordplay.
'a point' becomes 'e' (E is an example**).
'certainly' becomes 'yes' (I've seen this before).
'e'+'yes'='EYES'
'have' is the link.
(Other definitions for eyes that I've seen before include "(Paradoxical?) film with Cruise and Kidman" , "Parts of needles" , "Optical organs" , "Marks on potatoes" , "Potato seed-buds" .)