No, I don't think that transferring code or application development from one developer is a good idea. The reason why I say this is because if the other developer isn't competent enough to do the job then he will create problems for you in the future.

This is what happens when you transfer your code or application development from one developer to another:
If the previous developer created a bug in your code and it's still there, then you can find out only after many months of using your software. So it's better to fix all bugs before giving it to someone else.

Another thing that can happen is that if you give the task of maintaining your code to someone else, then he may not have time as well as interest so he won't be able to maintain it properly and he will end up creating more bugs than necessary which would affect your business badly. So transferring something like that should be avoided unless the developer/team has stopped supporting!
In such case, you shall have proper documentation and processes in place. That being said, I hope this answer helps!

For more information, feel free to book a call.

There's always a learning curve. Yes, it is a pain point and happens all the time. But there are ways to mitigate and make it more productive. I just happened to be on a KT today with my developers (one developer KT'ing to 3 others) and it went quite well. The biggest mistake I see is going straight to the code before understanding the business features, purpose and rationale it was done that wa, in this order.
Will be happy to go on a call and discuss further.