Why isn't it? After mirallas basically gave up our options out on the left flank consisted of Sigurdsson, Bolasie and Lookman. Siggy was usually played there, and was ineffective, until Bolasie gained full fitness and then he became virtually an undisputed starter despite the fact his form was awful.
Lookman played pretty well in some of the games for the first team, he played well whenever called upon for the u23s. His form for RBL suggests he could have translated that for Everton too but was never given a prolonged opportunity.
I suspect the managers we had over the course of the season didn't want to play a left side consisting of Martina and Lookman but when our safety was guaranteed, he should have been given game time.
As it were, the loan has ultimately proved beneficial for him. It is a shame that it is looking like it won't be beneficial for Everton, unless we get an above market transfer fee for him.