Why use zappa/chalice in serverless python apps?
Benefits. You can use known concept, and adopt it in serverless.
Performance. The smaller code is the less ram it takes. It must be loaded, processed, and so on. Just to process single request? For me that was always too much.
Let's say you have diango project, that is working on elastic beanstalk, and you need some lamdas to deal with limited problems. Now. Do you want to have two separate configurations? What about common functions? 

Serverless looks nice, but... let's assume that you have permissions, so your app, for every call will pull that stuff. Perhaps you have it cached - in redis, as a hole permissions for user... Other option is dynamodb, which is even more expensive. Yes there is nice SLA, but API is quite strange, also if you plan keeping more data there... the more data you have the slower it work - for same money. In other words - if you put more data, fetching will cost more - if you want same speed.
I am new to python and thought it would be great to have my very first python project running on AWS infrastructure. Given my previous node.js experience with lambdas, I thought that every function would have its own code and the app is only glued together by the persistence layer, everything else are decoupled separate functions.
In Python lambdas there are serverless microframeworks like Chalice or Zappa that seem to be an accepted practice. For me though it feels like they are hacking around the concept of serverless approach. You still have a full-blown app build on let's say Flask, or even Django, and that app is served through lambda. There is still one application that has all the routing, configs, boilerplate code, etc instead of small independent functions that just do their job. I currently do not see how and if this makes like any easier.

What is the benefit / reason for having the whole code base served through lambdas as opposed to individual functions?
Is there an execution time penalty if using flask/django/whatever else with serverless apps? 
If this depends on the particular project, what would be the guidance when to use framework, and when to use individual functions?