Bitcoins at first unique due to it’s large marketcap.
Yee, it is the first as it has the largest marketcap
Bitcoins are most secure if you compare it with others.
Yes, it has the strongest blockchain with the highest hash generation.
Not only secure, but also due to the decentralised nature of Bitcoins, it can’t be controlled by any government, therefore allowing it’s user to transact freely and independently.
Not controlled by centralized body like Vitalik Buterin or Do Kwon and other altcoins that still have a centralized developers.
At last Bitcoins transactions are anonymous, for which it allows safe transactions.
Bitcoin transaction is not anonymous, it is pseudonym. The transaction is transparent on blockchain, but can not be linked to people's identity if privacy is maintained.