Whether it's a "pain in the butt" is subjective, I guess. We drive into the parks daily, since we're offsite. We also never, ever rope drop. Not sure what you're comparing it to when you say "add 10 or 15 minutes", so can't answer that. But just some notes...
They have a ton of booths open during peak hours, so it doesn't take long to get to the ticket/pay window. People tend to be like a flock of sheep for some reason and stay huddled in just a few lanes, making those lines long. Look far left or right, there will be open lanes.
From there, it takes a few minutes to wind around to wherever they have you park. CMs will direct you where to park.
Take the tram from there to the front gate (or TTC for MK). If you're close to the front, maybe walk.
Note where you parked the car...you'll want that for later.
On average, I'd say from the time we get to the booth where you pay for parking until the time we're actually at the front gate (or TTC) is typically 10-20 minutes, depending.
EDIT: Oh, are you asking if the ticket booths add 15 minutes to your time, just to get through them? Sorry, slow witted this morning. As I said above, if you follow the flock, then yes, it may add 10-15 minutes. But look far left and right and you'll breeze through.