This is a real trade-off, but the "convenient" choice is not always bad if you have control over the situation.
As a transportation cyclist, some people I know think I must have superhuman willpower. But the reality is that I don't own a car, don't like the bus, and live too far away for walking regularly to be practical. I structured my life so that cycling is the most convenient option. I do this to save money and stay in shape. (It's good for the environment too but that's not as convincing to me. My pollution is a drop in the bucket, cycling or not.)
Here's an example most would consider less extreme: Switching to a "feature phone" or not using a cell phone at all. In that case, calling from a feature or landline phone becomes the most convenient option.
Few would be surprised by the general principle: When possible, structure your life so that doing what you believe is right comes naturally.
What seems more surprising are the specific applications, perhaps because they often are personal and consequently not applicable to others.
> It's good for the environment too but that's not as convincing to me. My pollution is a drop in the bucket, cycling or not.
Hey, don't sell yourself short! Of course an individual's pollution contributions are a "drop in the bucket". Just like a presidential vote is a drop in the bucket. In aggregate, these drops do a lot of good (or could do a lot of bad). You're walking the walk, so to speak. That inspires people to do the same. Keep it up!