[shmolyneaux]

One issue that isn't capture by that quote is that an escalator cannot be used while being repaired. If the maintenance person is away while the escalator is part-way through being repaired it's very reasonable to see a "Temporarily Out of Order" sign.

[masklinn]

Also escalators tend to be pretty bad at being stairs if you're not fit and healthy (and even then…), they usually have much higher steps and sharper edges than normal stairs, and are thus significantly less accessible when they're not operating.