Both ways are need for some basic capital and investitions. To trade you need big sum of money to feel the profit and for mining you have to buy necessary equipment, which is not so cheap, so, you have to look at all pluses and minuses of both mathods to decide what is better to you.
Mining bitcoin is not longer possible for ordinary Joe, serious mining is game of millions, 51% of total hash power is controlled by just five mining pools.
Buying BTC and trading is very much possible but it is nor necessary. If you don't need fast money then the simplest and the most effective way is buy and hold.
With every passing year bitcoin is growing, adoption rising, value increasing - that trend won't change, even despite serious scaling issues.