Bike computers pre-date smart devices, but if I get in a crash I’d rather have my phone in my pocket than attached to my bike and possibly destroyed.

A bike computer is also smaller, lighter, uses way less power, is cheaper, and you don’t really have to manage it like you do a phone (i.e. take your phone out, start up the app, mount it, make sure you don’t run out of battery or you can’t navigate or communicate).

A couple more answers:

- I’m not terrified to drop my bike with my bike computer attached.
- I’m comfortable leaving my bike computer mounted in the rain on a ride.

Bike computers are much smaller than phones. They also have mounting backs so they can be secured with a bike mount in what requires a 90° turn meaning that even if you crash going 30 mph your bike computer probably is still going to be attached to the bike AND not broken unlike a larger phone. Also they can record in a fairly universal file format that you can take your data anywhere rather than being locked into a particular app.

Over the past 10 years it’s definitely gotten easier to use a phone and there’s nothing super wrong with it, but if youre serious about riding then getting a dedicated bike computer is nice since it’s going to be more specialized.

Kind of like you can get a multi-tool to do a lot of stuff but if you want a really good tool you might want to get the one specifically made for it.

The main thing ironically is using less power than a phone to do the same things. Especially in really long rides, having the bike computer do all the tracking and show maps, etc. ensures my phone won’t be completely dead. The bike computer also won’t overheat in direct sunlight and the screen is matte and readable without backlighting unlike a phone. It also weighs less than a phone if you are a gram weenie and willing to leave your phone at home.

Separately, not all phones support ant (especially iPhones). Ant is a special low power protocol that other bike devices like power meters, cadence sensors, and heart rate monitors use. Especially higher end devices do everything they can to weigh as little as possible and still have a years long battery life and using ant is one of those methods. Bike computers all support ant and have better compatibility with all these other components. The bike computer will also usually support more simultaneous devices than a phone. Especially cheaper phones tend to have issues streaming data from 4-5 devices at the same time

Finally, bike computers do actually do things regular phones don’t. For example the new wahoo bike computer has a built in wind speed sensor that tracks when you are biking with or against the wind and adds that data to all the power and calorie calculations

That all said, I rode for years just using Strava and android health to track most things. The bike computer has made all that better but it is definitely an optional accessory that you probably don’t need if you are a casual rider