I agree this would be exceptionally helpful especially for us newbies who dont have a clue about deck building yet and just buy cards at random.
Even if it was just a column that shows your inventory against other decks you browse, that would be great.
Currently the only way to do it is to search for cards you want to use, copy decks and then delete them if they don't match.
What would also be cool would be the ability to sort user decks by total deck cost. For those of us looking to get ideas on a budget.