As for the other cryptos, we've seen reports and news that many of them have been 51% attacked and hacked. And to be fair for the traditional payment systems, they also have their own bad days but I think if we're going to compare them. It is that the traditional ones are more trusted by many because there will be an accountable company if ever something messed up.
Smart contract projects have many hacks and people use those platforms lost a lot of money in those hacks and investment in those scam tokens.
Proof of Work altcoins are less secure than Bitcoin because their networks have very lower hash rate that cause their networks are more vulnerable to 51% attacks.
If you wonder how more vulnerable to 51% attacks of Proof of Work altcoins, you can get some estimations from
How many confirmations are equivalent* to 6 Bitcoin confirmations?If I make an on-chain transaction, I choose Bitcoin blockchain to do this.
Yeah, those reports are like unstoppable news that keeps on coming and we're hearing from hundreds of thousands for the smaller ones up to millions from unheard type of projects that does have their own smart contracts. If we're going to look at those projects that are declaring they're more secure and better than Bitcoin, eventually you'll see that nothing beats Bitcoin for the better and higher security of its network. Thanks to it being a PoW and not a PoS which some altcoins think that being a PoS is better in terms of security but it's just all about being profitability.