Are you able to sell it back to finance a higher skill objective, for example, 85 herblore? No. In the event that he isn't able to raise money at RS gold all so there's nothing that he can trade back. Are you able to earn more by the time you spend in acquiring it? Yes. - There's no way you'd have enough money from BCP in the time required to buy a body.
In conclusion: Torso is not worth getting. Period. When you're not able to have cash , it's a good alternative. The only drawback I can see in slaying is the tiny prayer bonus loss. The defence bonus loss is tiny. Do you know how to prove this? The average income for a moneymaker is around 1m an hr. The inexperienced players for that long to master BA and by then, you'll have enough money to buy BCP.
I've never said that the def bonus is important. If you read my other threads, I prefer str to def on any day of the week. The fact is that you cannot sell torso back which means that the point is negligible. I can assure you that "average" money maker cheap OSRS GP is not even close to 1m per hour. There are only a few methods that will make that kind of.