Allegiant has flights out of my local airport twice a week. One on Wednesday, one on Sunday. If I'm booked on a Wednesday flight and it gets canceled, I'm stuck until Sunday and I miss 4 days of my trip. Or, if my return flight gets canceled, I'm stuck in Florida for an extra 3 or 4 days that I didn't plan for. For me, the risk isn't worth it. I'll either fly a bigger airline or drive.