UI on phone apps still is terrible. Have you ever used a desktop with high-end gaming peripherals (fast monitor/keyboard/mouse), running a light desktop environment such as LXQt on Xorg, with animations disabled? The feeling of responsiveness leaves all mobile devices in the dust. Any modern CPU+SSD is fast enough, but good peripherals are still rare and make a huge difference. Most phones are still running 60Hz displays. A touchscreen is inherently clumsy compared to mouse+keyboard. Mobile UI feel is worse than desktop computers from the 90s.