You don’t need to buy a second dongle, just make sure you don’t lose or break the one you have.
I don’t find the dongle scheme a burden and prefer it any of the other copy protection methods. With the dongle I don’t even have to remember any serial numbers or activation codes just make sure I look after my dongle and whenever I install software it’s ready to go.
Why don’t you elaborate what more modern and efficient solutions to copy protection there are?