1)You can always use Bitcoin for any transaction you want considering the fact that you are ready to pay the average fees at that time for confirmation of your transaction easily.

2)If the network is congested which means memepool is full of unconfirmed transaction then you need to pay higher fees or use RBF feature to confirm your transaction.

3)For regular transaction Bitcoin needs to be accepted by majority of people in the market because all are not buying Tesla and some other stuffs with their coins.
 
In the end it's your coins and your money and it is how you use them.