I would suggest anyone to hold both of them.
They are needed anytime.
Alt os good if you can get the train.
BTC is good if suddenly your favourite coin is dropping ao you can collect more or pump it.
Keep both of them, use also hard wallet may be better to store it
Though both are doing well at present but I will prefer bitcoins over altcoins. Bitcoins are very old player in the crypto land but altcoins are very new to the market. They are just kids. I believe that altcoins will need time to stabilize their position in the market but bitcoins are already ruling the crypto market.
Both are my choice as well. In your comment you described bitcoins as someone older, and alts as kids, my opinion since forever is that much better is to invest in kids then in old players.
Its always depends from what kind of plans someone have, quick profit or long term holding. Its good to hold bitcoins, but its also good to hold some alts, both can bring profit we need to agree with that. Everyone here would like to know which coin can bring highest profit in next couple years, but we can't know, we need to risk now and I'm sure in this, more we risk, more money we invest more profit we will make in future.