Given that this is a RWGPS thread, maybe some actual information regarding battery usage of the app while riding would be useful to see if it lives down to the definition of 'eating' battery.
Here are 2 data points from me:
1) logged my morning commute today with RWGPS. Usual RWGPS settings, screen turns off quickly, but is set to wake at a touch or wave of the hand. I woke the screen about a dozen times on the ride. 42°F temperature. Phone dropped 2% in 40 minutes. So 3%(~140mA)/hour which is not much different than if it was just in my pocket and not logging the ride.
2) navigated the ride home: All cues(over 50 cues) turned on, spoken audio and visual; Screen on 100%; streamed audio book to my Aftershokz, location sharing on to my family, went off course a couple times, took several photos- so basically worst case scenario. Total battery drain was roughly 14%/hour.
I guess you can call that eating battery although attributing it to RWGPS is dubious. 58 minutes of RWGPS screen time+ 1minute background use in a 2 hour window accounted for 3% of the battery usage in that time. 1 minute of camera use drained as much battery as 1 hour of using the gps subsystem. Amazon Music accounted for a third of the battery drain in that timeframe.
As a rule, it's not gps tracking that eats a phone battery. It's all the other functions it can perform at the same time. A GPS computer doesn't have the same abilities/drawback for better and for worse.