I think investing one's Bitcoin is one of the better ways of growing Bitcoin. You can loose money in trading but if you invest properly then good returns will be standing at your doorsteps. You can invest in various altcoins like ethereum and monero. You can also invest in various ICOs.
Yes, definitely investing is a good way to grow our bitcoin, especially investing in altcoin and ico, it can bring us a lot of profit. Just we have a good prediction, a right choice, our bitcoin will grow very quickly when we invest, however the problem we face is not small, the risk comes from investment is quite high, the worst case is that we can lose everything. We need experience and knowledge before investing, that will limit the risk and increase our chances of winning, investment is not simple