As others have said, it comes down to risk tolerance, environment / use-case, and ability to stomach a big repair bill / effectively buy a new one, if something catastrophic happens.
A few of the considerations that I think factor into the decision:
- Is it a newer model refresh / generation? (First year of new model, eg. 2021 MBPs, M4 iPad Pros with Tandem Oled screens) May make sense more than usual to be covered in this case, as we get a better sense for whether a model generation is glitchy/prone to issues (eg. butterfly keyboards in the 2016-2020 MBP generation)
- Is it a more expensive / spec'd out version? (eg. ram, storage upgrades)? AC pricing is interesting in that it's the same within a model type (eg. 16" MBP, or 15" MBA). So within all 16" MBPs for example, AC is same price regardless if it's the base model, or a hugely upgraded version that's >2x the price. All things equal, with higher $ configs, AC is a lower cost as % of brand new... makes more sense more often
- Do you have kids in the home that run around / knock stuff over? Are you going to be taking your Mac around a lot / travel with it, or will it just sit on a desk?
- Do you tend to be a little clumsy?
- Financially + mentally / psychologically, how much do you value the peace of mind of knowing you're covered? How much would it "hurt" (financially and mentally) if you didn't have AC and had to basically replace your Mac with a new one, in the low probability chance something happened?
Lot of factors for when it might make more sense than not. At the end of the day, it's insurance, Apple "makes money on it" in the long-run over big sample size... that doesn't mean in won't be worth of it for you in certain scenarios. But as far as insurance goes, I think Apple is the best at servicing / treating their AC customers right.
Unlike almost every other extended warranty-like insurance, where with any claim, the insurance folks are looking for any reason they could deny your claim, I find Apple does the opposite, and tries to do everything they can to approve your claim.