The workflow connection profile is saved to the local workstation where the Designer is installed rather than server side. Because of this if the user get's a new workstation they lose their repository information and have to enter it again.
This opens up the opportunity to enter invalid credentials and is unnecessary if this information was saved server side.
People replace workstations all the time, the server should know how to connect to it's own repository(s) while a vast majority of customers only have 1 repository anyways so should never need to be asked.
Today I had someone enter Admin instead of the service account and it allowed them to connect with the Admin account. Because of this it created an infinite loop since the service account did not match the starting rule conditions preventing infinite loops.
I really can not see any benefit to storing this information client side or even prompting which connection you want to use each time you create a new workflow.
What if it defaulted to the primary repository configured and if I happen to have more than 1 repository or service account I could switch it if I like?