With your first part of the sentence you already put your second statement in a nuanced context. But I'd argue that "it is sensible" puts too little weight on this side of the argument.
We've all been there: You're new to a field and climb the Dunning Kruger Graph. At some point you're standing on the first hill and start "argue on [your] own".
Most things have already been said and argued. And most probably so by people more knowledgable and intelligent that me and you. And exactly those arguments are the 'history of philosophy'.
We're probably all better off if we learn to move within this tightly knit web of knowledge and be very cautious and conscious every time we leave those trails and 'go on our own'.
That being said, it is mandatory to view the history of philosophy not as the whole ball park but jump over the fence occasionally. Whether we hurt ourself by doing so is almost certainly dependent on how comfortable we are with what has been said and argued before, eg. history of philosophy.