The safety of investing in Bitcoin ahead of any other coin isn't debatable because history and market values have proven that there's no other safer crypto coin to invest in apart from Bitcoin. Bitcoin volatility is lower than any other coin in crypto market, the future values also shows that Bitcoin is a stronger investment option for any investor. Unless you're a crypto trader that prefers short term investments to long term, then you can be advised to study the market and invest in few altcoins than have a high future return value but if you're a long term investor, Bitcoin is not just the safest but also the most profitable coin you should invest in.
Bitcoin is volatile just like every other coin and token out their infact its even more volatile than some Altcoins out their same way that some are also more volatile than Bitcoin, what makes it different is the fact that it can recover from every fall that it experience it have overcome a lot and have proven its self over the years which have made people to have trust on it, not like some other coins which if they fall today you can’t predict when next they will see green market again.