It depends on your needs. I watched a fascinating video yesterday that showed that the difference between the M1 Pro/M2 Pro/M3 was about 10-20 percent. To me, that isn’t compelling since the earlier models are much cheaper now.
I have a 2019 Intel Mac and with 32GB of RAM, it does everything that I want and more. I have used an M1 laptop before and it was a joy to use. Everything was instant. I like that it saves energy which can save both money/time. Still, if you have had a Mac in the last 4 years for nonprofessional use, it is hard to argue that you need to upgrade.
Now of course professionals always need what is the most efficient. You might also justify a purchase if you are environmental. Still, you are trading one kind of waste for another. If you give the old computer to someone else then you aren’t wasting it, but you also haven’t changed the equation. It still uses energy you just aren’t paying for it. I strongly wanted to buy one in the past to be more environmentally friendly, but this is the same issue with EV cars.

Yes, you can help the environment by buying an EV but I think the research I saw said that you have to keep the car for at least 3 years to justify buying it. (According to a study from Argonne National Laboratory about 47,000 miles @12,000 miles per year typical average) Now people are keeping their cars for 13 years but higher income people who are buying them tend to trade cars to have what is newer. Yes, some of the components are recycled but there is still the entire lifecycle that you have to account for. It’s not always clear that doing what seems intuitively true is what is the best. Truth is often paradoxical.
Let’s say you buy the laptop and you save energy. Great. Then what happens if you have an accident and ruin it? Or did it get stolen? Then you buy another one increasing demand. Yes, that could happen to your old computer but at that point, it has given its value to you and you aren’t out the money. Most people don’t have insurance that covers personal goods, and even if you did claim it on your insurance it would simply raise your premiums. By having a high-value good you attract attention and more likely will have it stolen. I know this firsthand.
Right now the EV market is slowing down because it is appearing that just getting EV vehicles is not the answer we hoped it might be. Now urban planners are reconsidering the value of better city planning and mass transit. I love that we are getting more holistic with our decision-making and not putting hyper-individualism at the top of the chain all the time.
Getting back to M3 this is a question of values. Do you need something that you may not notice at all, or rather invest the money in the well-being of the community? I think Apple is going to have a hard row ahead. People have computers that can do everything they need them to do. Only professionals want more and each year makes them less dependent on new models. Eventually, we are going to hit a plateau where the computing power is enough and further models don’t offer any meaningful difference. Perhaps we are already there.