By promotions you meant the deposit bonus offer? If yes, I don't see any reasonable argument why you shouldn't use a deposit bonus and boost your trading account. I am aware that some trading gurus are strongly against this with some baseless arguments that using such promotion will speed up the process of you blowing up the account.
This is not renewable.
If you trade with a $1000 account size, without a deposit bonus and without a solid risk management strategy, you will probably end up blowing up your account.
But if you have a solid risk management strategy, trading with a $1000 account size, or trading with $2000 does not make a difference. Expert one, with a large account your projected profits will be higher.
So yeah, I recommend you to use those promotions only if you have a solid risk management strategy.