I don’t see any downsides or arbitrariness of this suggestion, I mean, there are some services I will use for one month, and I intend to use it for that month, but it happened before where I would forget to cancel it, and this has happened to other users too, by default, auto-renew should be off, I don’t really know any strong arguments that can go against this point, I mean, auto-renew can be useful, but there are many cases where it could be harmful and even though people do forget it, it might be a tiny bit deceptive in some cases.
I don’t think I’ve ever had a free trial that ended the moment i cancelled it. Whenever I sign up for a free trial, i immediately go to cancel. Usually it’s for amazon prime, or kindle unlimited.
There may have been one case where canceling meant instant end of the trial, in that case, well, tough, I’d rather not have a month free than have to remember to cancel it manually. If they don’t want me to try it, i won’t and will definitely not become a paying customer.