Just because it's "common" doesn't make it a good idea (and I would argue that it's a common technique, anyway).

Weight loss isn't based on what is being used for energy, it's total caloric expenditure in the 24-hour period. If what you write had any significance in terms of weight loss, HIIT wouldn't make any sense and wouldn't work. Meanwhile, you're potentially burning half as many calories by performing fasted SS because you don't have enough energy to perform intense work, and if you did you'd risk causing protein degradation and muscle wasting.