You can but you cannot make some quick money if you do so. But you will be safe if you do this. BTC is an established coin and it will not go down soon. There are many backers for BTC.
You cannot benefit on the success of altcoins that might pump compared to bitcoin, there are new altcoins that is not touch
by the whales yet and it might pump to the moon once they see the development of such.
Research is really important, you can make more money if take advantage on the dump season of altcoins because definitely it will come back strong.