Sure it would make sense to do it indefinitely. If you can make it work for bulking, there is really no reason not to do it. I don't think you will avoid all fat gains but you can definitely minimize it compared to a traditional bulking diet. It just makes sense to concentrate your calories during the time when your body is building more protein.
The first con (for me anyway) is that it can be difficult to work around schedules. My work schedule varies so much that some weeks I can strictly adhere to it and other weeks I cannot. Also some weeks I can lift religiously and some weeks I work so damn many hours that I cannot lift much if at all.
The other con is that for larger individuals, it is difficult to get enough calories in the eating window. I currently weigh 240 lbs, due to my weight and my high activity level, I have to eat a minimum of 5000 calories a day to gain weight, which is very hard to do within the eating window. There is another bigger guy here, Brixtonian, who has attempted an IF bulk and couldn't do it for the same reason.
If you only need 3000 or fewer calories a day to bulk and you can work it around your daily life, then I believe it would work great. I also believe that IF is better for overall health compared to a traditional diet but the evidence behind this is not yet rock solid.
Squat - 485 lbs
Bench - 315 lbs
Deadlift - 635 lbs
Total - 1435 lbs