Doing something is better than nothing. I drive my car once in a blue moon now as most of the time I'm on a motorbike which is inherently better for the environment on fuel consumption and not idling in jams.
The less fuel you consume the better full stop, so the smaller and more efficient the vehicle the better it is environmentally.
I do consider briefly that getting rid of a vehicle for someone else to end up driving it (and probably doing a lot more miles than me) isn't improving the environment in the slightest, it's just shifting the vehicle and associated guilt away from me.
Scrapping it when it's so far away from end of life would also be environmentally unsound.
So I look at it, have feelings of warmth as it's the car my children grew up with and I have a lot of memories attached to it then stop smiling when I consider what it now represents, resolve to sell it and backtrack. I've been doing that for about 5 years now