Well there are different reasons to suspend your account. Most of the high up witnesses will have multiple redundant servers, but a lot of the lower ones will only have one. If they are going to go on vacation and don't want to have to worry about their server going down (and missing blocks) while they are gone, they may temporary disable their account. I turn mine off (for just a moment) any time I'm going to do updates on the server that could potentially cause it to go down, then turn it back on once I am done.