TPS53355: Recommended Replacement

Part Number:TPS53355

Hi,

I have a question about TPS53319 and TPS53355.
Looking at these products page, other devices are introduced as "recommended alternative parts" for these devices.

TPS53319→ TPS548A20
TPS53355 → LMZ31530

Could you tell me the background of these statements?

Best Regards,
Yuto Sakai