Surely there's a limit. My previous phone (Nexus 6P) had a 2560x1440 resolution on a 5.7" screen. My current one (S10+) has the same, but taller (3040x1440). However, using it in plain HD mode (something x 1080) looks exactly the same.
I agree that high PPI is very desirable. On my 16" MBP and 4K 27", I love being able to switch to a different resolution without any noticeable visual defects. But too much is just too much. My Nexus 6P, being one of the earliest super high res phones, basically smoked itself to death trying to push all those pixels. I would have traded that useless super high res for a much better battery life and no premature death.