Do other minds exist? Does the external world exist? For that matter, do I exist? Imagine seriously considering such questions. Then, imagine asking yourself why you do so. Then, consider that brilliant people have devoted time and effort to their consideration, have written regarding them extensively, and that students have been compelled, or induced, to read those writings for many, many years.
It seem self-evident that these questions are not serious; that they are in fact foolish, and that we regularly treat them as such. We always act "as if" we, others and the external world exist. In fact, we never really doubt that this is the case, nor do we have any reasonable basis on which to doubt. As we live our lives, we are not faced with such questions. They present no problems which must be resolved by us in "ordinary day-to-day life." The consideration of these questions, therefore, make no difference in our lives.
It may be argued that their consideration can have educational value, and I think that's true. Their consideration can be an engaging and useful intellectual exercise. But their consideration has not been treated as such typically, and if they were thought of as educational exercises this would not explain why they have been, and are, treated with a kind of reverence and accorded a significance they plainly don't have to us if our conduct is any measure of significance. It may be argued also that their consideration at certain times throughout our history can be explained and justified. For example, Descartes can be said to have given them legitimate consideration because an old order was crumbling and a new one was needed. But this doesn't explain the fact that they continue to be debated, or the effort devoted to their consideration now.
Is it possible that those who devote time and effort to such questions do so knowing they are engaged in a foolish quest, but are, nevertheless, content to continue? It seems a bit harsh to claim that this aspect of philosophy is a kind of glorified playground for the fatuous. Perhaps there is something in us (or certain of us) which makes us ponder and concern ourselves with that which makes no difference in our lives. Perhaps such philosophizing is a kind of OCD.
Regardless, I can't help but feel regret whenever I see such questions being debated, especially by intelligent people, and wish that such intelligence was being devoted to the resolution of the serious problems we actually must face in life.