Is this true? I'm also relatively new to this but there are some great altcoins out there which have huge potential. Surely investing small amounts of fiat those which would give you a lot in that coin is low risk and could turn out to be hugely profitable (like Bitcoin is) in the long run...

Bitoin is expensive now and with its flaws, there's a risk your investment in it will go less far and Bitcoin could flop.

Just my two cents. For full disclosure I have Bitcoin and alts.