Great points, I'll try to explain the thinking at the moment.
The kind of simple power systems the lock will be using are beyond 99% reliable nowadays, but failures can still happen. The locks will require juice to open, not to close, so if there is a power failure then you won't be able to open and use the lock. If you're unlucky enough to get a power failure while your bike is locked then there will be an emergency function in the app to alert us so we can go and fix it asap, I won't expect people to wait around so we would pay for a taxi to get you to wherever you wanted to go and deliver your bike to you once we've unlocked it.
As for magnets, the locks will use powerful rare earth permanent magnets as part of the locking system (hence juice only needed to open the lock). As such the electronics will be shielded. As with everything, enough force can overcome barriers, so if the perp had a big electromagnet it could still scramble the code and cause the lock to stay in locked mode. same problem as above. But then you have to think about why someone would invest in a big heavy electromagnet and drag it around, when they can achieve the same result with a couple of drops of superglue in a traditional lock.
With regards to hackers, if you read the information about those hacks they are human errors, not hacks of the encryption. In the case of the Capital One breach, the hacker only got access to data because she found a door that was left open so to speak: "The F.B.I. agent who investigated the breach said in court papers that Ms. Thompson had gained access to the sensitive data through a “misconfiguration” of a firewall on a web application"
Please keep asking more, having the concept challenged is the best feedback to design it to be stronger
