Filters: Multi Coated or not

[Patagonia]

Looking at including some filters in my equipment (CPL, ND´s and yellow 81 or similar for mid day landscapes) and had previously decided they had to be MC.
Now, reading several threads in the forum it seems MC or not MC is not something that is discussed as an important issue, so if its not important to discuss then is not important to have it? in short, is it worth paying the extra for the MC or a normal filter would be enough?

Also reading some posts it seems going for the most thinner filter is the rule (as long as it permits to screw another filter)
regards