[lakraboob]

We need to understand that the Buddha taught Dhamma in various levels for various people
(e.g. monks, kings, soldiers, merchants, farmers etc).
If we can connect all jigsaws, we will know what level is for Dhamma we are discussing.

It is like teaching maths in kindergarten, primary school, secondary school,
high school, and university which have various and different levels.
In kindergarten, a student may say that the purpose of math is only to count oranges in a busket.
In the university, the purpose of math is more advanced and not the same.

I expect that Ajahn Chah said this quote for people who did not have much/deep knowledge in Buddhism.
They needed something easy to understand. Also Ajahn Chah's quote is correct.
If we 'truly accept' that we are not self and there is no self, then we will not have to be physically born into a belly again.
I personally also agree that being in a belly is not happiness.

Although the ultimate goal is to be not born, there are Dhamms for family lifes.
The Buddha taught Dhamma to not only monks, but also household life people.
(The Buddha did not require that all household life people to be monks because it was impossible anyway.
And, also there would be no household life people to denote foods to monks.)
So, when you read the Buddha's teachings, you need to consider whether such Dhamma is for whom.

For example, a monk needs to hold 227 precepts while a household life person is required to hold only 5 or 8 precepts.
Certain Dhamma for monks and household life persons are different, but many of them are similar.
We need to consider them carefully in details, and then we will not be confused.