There's alot of options to "bulk". Let's say 3 months of bulking and then 3 months of cutting as a half year period. Then another way is to eat just above your daily caloric need and possibly gain for 5 months and then cut 4 weeks. If your starting point and goal is to lose weight and get certain fat %, then there's no need for bulking. The worst thing you can do is to stay overweighted for a long time and increase the amount of fat cells in your body and then when cutting, you still lose the weight but you don't lose the amount of fat cells but instead, they're just decreasing in size. On top of that, everybody has their own kind of set point where their bodies feel the most comfortable, atleast fat % wise. If your set point would be let's say at 20% and you would stay at 15%, it requires more than doing the sauna for 4-5 times a week so it would most likely require a total change in whole lifestyle, so it wouldn't be yo-yo effect with the weight going back n forth.