SugarConnect Setup Question

Hello! I think this will be pretty straightforward but I wanted to check first.  We are about to do a trial of SugarConnect and I am at the point where I am setting up the tenant. We have never connected our sugar instance to our 365 before. 

my question is - will setting SugarConnect up have any impact on my current users - specifically ones I am not going to assign sugar connect to? Or is it just business as usual for them in terms of sign in etc. 

next question - if we decide not to go with SugarConnect is it easy enough to rollback and decommission or is it a hassle?

thanks so much!