These are routing nodes, they have in-memory storage and they only store two things:

1. routing table to nodes closer to a target info hash (basically a hash table automatically sharded)

2. small packets of arbitrary (and other non arbitrary but less relevant to Pkarr) data in an LRU cache.

Nodes churn all the time and even when they don't churn if their cache is full your data might be evicted.

so it is great for censorship resistant routing, not so much for data durability let alone storage of large blobs.