...means nothing with respect to carbon emissions.
In contrast, using the "renewable energy source" directly yields much higher net benefit.
Only for certain values of "benefit."
Liquid fuels are extremely energy-dense, portable and stable. Yes, you might trade total net energy for that benefit, but that's not a deal breaker if the energy is extremely cheap (renewable). You can have battery powered cars (of which I'm a major proponent), even battery powered/hybrid trucks. You're not going to have a battery operated cargo plane any time soon, nor an all-electric cargo ship, and I can't imagine a battery powered rocket.
Then there's transport. You can put liquid fuels on a truck or train car, or on a boat, and transport it anywhere. You can even use a pipe: A 6" pipe carrying diesel fuel can transport as much power as the entire output of a large nuclear power plant (~1.8GW).
The density and portability of liquid fuels is a HUGE benefit and worth paying the energy price for in many circumstances.