Hmm,
Because BTC sucks,
it is outdated code with performance problems that will not be fixed,
because it's masters in China refuse to update their code, so they can keep their greater than 51% domination of BTC.
FYI:
Try almost any altcoin , and you will soon agree BTC sucks.
Outdated code? Bitcoin is designed to have blocks occurring per 10 minutes to ensure the fixed supply of coins and security on the transactions. The reason for Bitcoin to have 10 minutes transaction is because it is an amount of time that can be used to prevent double spending.
The shorter the confirmation time, the less security it would have due to the higher number of orphans and so on. Alt coins are extremely volatile with many of them sacrificing confirmation time for security. Hence, merchants needs to wait for more than one confirmation.