Well it was just a thought, but most of your objections can be mitigated against...I disagree with this for five reasons:
Well maybe but I counted 17 cycling specific ones on the google play store and 10 on the Apple store. On ConnectIQ there were a couple of exceptions but most of the nav apps seemed to be for watches. I've no idea about the app ecosystem for Wahoo devices though.
- The choice of cycling specific navigation apps is similar on a phone as a bespoke device.
Debatable. Phone screens are much bigger for a start which counts for a lot. Phone screens vary a lot in brightness and contrast too. I find the Garmin default font is not the best for readability. which is one of the reasons why I went from the 530 to the Explore 2.
- Phone screens are not easier to read than a purpose designed GPS unit
Again this is debatable. A standard phone yes probably slightly more likely due to being a larger device sticking out more. But ruggedised phones are available, as are very protective cases. I once dropkicked my phone down the road. I was running for a bus and it fell out of my pocket and bounced off my foot! It was in a decent case with a screen protector and was totally unscathed.
- In the event of a fall a phone screen is more likely to break
Depends on the phone again. Some are better than others, and the battery health of a second hand phone depends totally on how it's been used.
- Battery life is very poor in this situation especially if using an older second-hand phone
I use my phone for google maps nav in the car and I don't always plug it in. I reckon it would last 5 or 6 hours from a full charge, and that's with 4G data on to download maps on the go and live traffic, plus bluetooth to the car for music. With tweaking of settings, pre-downloaded maps and turning off wifi and bluetooth you could eke it out more.
Well, you could always top the phone up when you stop for other reasons. And cases with built in battery packs are available. There are several solutions.
- Who wants to stop to recharge a phone? Riding with a power pack attached to the phone is unreliable.
I agree it's going to be a bulkier solution than a dedicated device and might be more of a lash-up but could be a viable option for some.