Focusing on Bitcoin alone is not the best option for now, investors need to invest more on some alt coins with great potentials. It's just a test of time for alt coins , they will definitely be back on track
Actually this is a good strategy and it has proven profutable even for noobs who dont know much about other coins.
Bitcoin is secure, safe, and has the least tendency of going to zero in d case of a market crash, so i think BTC is a good option for investment