The reason this is important is that not all roofs are created equal. Unfortunately, some of them are more susceptible to things like mold, wear and tear due to harsh weather conditions, and rotting.
If this is the case, then it may be worth it to get a roofing assessment of how durable your roofing deck is, especially if you live in an older home and have not checked on your roof’s stability in quite some time.
With that being said, if your roofing deck is made up of plywood like most traditional ones are, then there is such a thing as mold accumulating simply from the moisture and condensation that builds up over time in your home.
If the mold sits there long enough or if for some reason, pests and termites eat through the plywood, then it could potentially make it easier for a leak to transpire.