But at the same time, the Reading List can be sorted by last update, so it's not like you really need this...
Although you could say the same thing about "1k books on a reading list" here. It can also be a hassle to go through sorted lists, if you don't check them daily. Especially, it is also a difference between "checking each day and getting disappointed" and "getting a notification if there is a happy occasion".
In web-development every single click used for a feature reduces the amount of people who are willing to use it. Checking your reading lists daily through extra clicks will turn off a lot of readers in the long run, especially on a site like this, where a lot of stories don't have defined dates for the chapters or can go on hiatus for months without any announcement. Even if checking it is only 2-4 clicks a day, it'll add up...
Adding a bell would be a clear improvement for these cases.
That said, as this is a free hobby project, this isn't site-breaking, and Tony's workload will decide...
And we know how that looks :D