Two things can be true at the same time

I can have an opinion that phones have sufficient battery life AND be curious what kind of person needs more than the provided battery life

The example of someone hiking so far does not make sense since a phone is idle when hiking and will last the entire time easily

In a hike you probably want to use your phone to look up the map/gps location, take photos etc. Ime iphones are struggling with this use case a bit without a power bank. Putting them in low power and airplane mode, while using a lightweight app for navigation with downloaded maps helps a lot, though it is still not gonna take you as far as other phones with larger battery life. I would never go for a hike where I know I need my iphone without a power bank with me. But not doing these and using google maps to navigate will not take you very far into the hike at all.