Ragakkhayo Nibbanan.
There are three types of raga: kama raga, rupa raga, arupa raga.
To put it simply, PS describes how raga turns into kaya.
If you have yet kama raga, you will be born in kama loka. (Kama kaya)
Samely, rupa and arupa raga gives you (a)rupavacara kaya.
So, the continuation of samsara is to continue with getting kaya.
As long as someone thinks kaya is a good thing(have raga), the creation of kaya doesn’t stop.
Sakkaya ditthi is sath + kaya. So put together, it means samsara is good for oneself.
Kaya comes from raga. Ragakkhayo is the end of kaya. That is why there is no kaya in Nibbana.
Also, if there is no kaya(manomaya), there can not be citta too. So, there is no citta or cetasika in Nibbana.