Bitcoin is definitely safer, but some altcoins may provide higher short term returns, but I think it's not worth the effort to keep up to date on all altcoins so that it is worth to invest in a bunch of altcoins.
I agree but investing in an altcoin is a gamble , you might get a high amount of profit in a short time and you might also lose it on a short time ! investing in altcoin is much challenging than bitcoin , so for safer investment I'll go for bitcoins !