This was the issue I had when deciding on whether to buy or not.
I currently have the old SE, and the battery life is shocking, so the one thing I want from a new phone is better battery life than that.
Apple says "lasts about the same as an iPhone 8" - well, what's that supposed to mean? I don't have an iPhone 8, so it's a meaningless statement. It would be helpful to know how long the battery lasts in the new phone, not how it compares to some arbitrary predecessor.
In the end I purchased anyway because I'm never going to be able to afford any other iPhone, so it's this one or nothing. But it would have been helpful to have a battery life information that's actually meaningful.