Because he is not a box to box player, so you play him instead of Matuidi and he does not do half the work, and not many midfielders have Matuidi's workrate anyway.
All our midfielders apart from Matuidi and Khedira are dm's, is it really a suprise as to why those 2 always start, i forgot Ramsay, but he should take over Khedira's spot if he ever gets fit, i prefer him there than at 10
All this talk about Pogba but Kante >> Pogba for us imo