Anytime your smoker breaks down, the weather rolls in or you just don't have the time. The oven is a perfect substitution. I realize mine is a gas oven but mine will go down to 100 degrees, thats the same as my smoker. Cook on the smoker till when ever is convienant, say at the first stall, or when ever the smoker breaks, or until you decide to foil. Whatever trips your trigger.
You do although need to try and maintain the smoke as long as possible. 100 to 140 IT (internal temp) being the optumium for smoke absorption. Your oven will be as good as the smnoker, just lacking that good smokey goodness.