In my mind they're different things. GPS for navigation is often useful and occasionally infuriating. GPS for logging tracks is lovely, if you care about such things, and hard to get really wrong. Bike computers are for giving you a simple display of your speed, the time of day, and maintaining a bike-specific odometer.
It's a bit like the difference between a watch and a smartphone. Yes, in both cases there are products that usefully blur the boundaries, but doing one thing well is a sound philosophy.
More critically, and as the OP is asking for, a traditional bike computer is a useful backup to a GPS for navigation when combined with a routesheet. On that basis, I think it's right to prioritise reliability over fancy features, and reckon they'd be wise to avoid anything that requires remembering to press a button to wake it up before you start riding.