This pdf lists it as a class 4, which is the lowest, and it can't be used for exposed
structural members, but that doesn't exclude it from use as decking.
It says that the heartwood service life is only 5>8 years, but if it had a well maintained coating, who knows.
The price is certainly
very attractive, and I hate TP, but you'd be paying closer to double that price for merbau which is the most common next step up from TP.
There's some decking experts on the boards who may chime in with some advice.