In making your ad visually different, you have probably created a distinct identity for it. This is a very valuable property because it sets you apart from all the rest and you should endeavour to maintain and build upon that identity through consistent application. Every time you make the same, or very similar visual statement, the identity is made stronger. It grows and flourishes.
Suppose you are out on the town and someone hands you a flyer advertising the Pink Pussycat Club and you think, "That looks interesting". The paper is pink and has a lighter pink cat logo along with a slinky typeface. You turn down a street and there in the middle distance is a pink sign with a pale pink cat on it. You are there, there's no question!
Had the flyer or the sign deviated from the 'look' you were expecting, the club would not be so easily found.
So many banner ads bear no relationship whatsoever to their destination and they are missing out. The ad and the destination page should belong to one another because that helps reinforce brand identity - and confidence.
Confidence is the key to successful marketing communication.