Almost every cyclist I know uses their phone for tracking or navigating. I use mine to follow topo maps while bikepacking. It gets the job done but it's a bad experience for these reasons:
1) Because of the capacitive screen you can't control the phone if your finger is wet, or when you are wearing a full finger glove
2) Smartphones are so bulky they actually change your center of gravity if mounted to a bar
3) You can't read the OLED display in bright sunlight
4) It shortens your battery life, leaving you at risk of not having a way to navigate
Since dedicated GPS units are expensive and don't have great topo maps, my solution is an E-ink auxiliary display with physical buttons. Like a smartwatch, it uses Bluetooth to access the GPS and wireless features of your smartphone, which you keep in your bag or pouch. It is super light, has weeks long battery life, great visibility in full sun, and the buttons allow you to control it with gloves, in any weather condition.
