Doing signature campaigns is pretty safe to grow your bitcoins and with a good campaign it can be very profitable, what of course is important for us all.
Trading is also a option but the risks are pretty high and you can lose money from it real fast.
Signature campaigns are to EARN bitcoins but what you will do with the bitcoins so earned ? Thats called as growing bitcoins for example you earn bitcoin with signature campaign and then invest them in gambling sites so you are earning bitcoins and growing them too double impact

You are also confusing the whole thing because you are condering put bitcoin into gambling as a way of growing bitcoin. Puting your hard earned bitcoin into gambling can not be a good way to grow your bitcoin as gambling is a game of chances and you don't have assurance you are going to win, instead invest in bitcoin trading.
Yes Gambling is never been good choice for grow your bitcoins/money because its game of chance and your can lost all your hard earned money in few minutes currently best option is investing in any good site or doing trading for fiat or alt coins is much better just need some research and hard work from you for good profit