Yes, but not insanely so. A compact car for a week with Share Now is €42/day, and with Sixt it's €32/day. In a lot of cases, I'd happily pay that for the 1-2 hours of saved time in not dealing with the rental company, or booking things in advance.

I know specifically a lot of my friends who basically fall into that category: don't own a car, and decide same-day that they want to do a weekend trip, and would rather pay €20 more to not deal with contract, aggressive up-selling, pick up and drop off, refueling, inspection, etc.

It usually is, but there is a reasonable ‘convenience factor’ that sometimes tipped it.

Of course, multi-day long road trip in another country that I plan in advance, hit up Kayak and the major agencies, no question.