Because if the enterprise service stops working you'll have someone working on it and giving status reports on progress in hours. In residential you'll have someone look at it in 2-3 days if you are lucky.
Anecdotally, a few months ago, there was a transformer-caused fire a couple of blocks from my home that burned a telephone pole, disrupting power & internet service to a few city blocks of single-family homes. Crews were re-routing power as soon as the fire was out, and the ISP crew worked through the night to replace the pole and restore internet service.