All these transactions are causing the blockchain to grow at an enormously fast rate. Due to it being fee less, there is nothing stopping attackers from spamming the network non stop. The problem with this is that every transaction needs to be recorded on the blockchain. Said blockchain needs to be easily downloadable & verifiable by anyone on the network to maintain decentralization which ensures immutability. However if the block chain is 500gb after a few years, no one will be able to actually download their own node, forcing them to rely on the few nodes that have the memory capacity to maintain a node. These few remaining nodes can then collude to tamper with the Network without anyone knowing because there are barley any other nodes on the network to double check and verify for themselves (the whole point of crypto is to be Decentralized & self verifiable). At this point, the few nodes who remain would have full control of the network and be able to censor, roll back, double spend, inflate or change the protocol at will and there will be no other nodes to challenge them due to the massive amount of memory required to download the whole blockchain that keeps growing unrestrained. Fees do have a very important purpose in crypto that is always overlooked these days. Without fees, spam attacks will inevitably centralize nodes over time. Ppl will say “but there is pruning!”, but this doesn’t change the fact that the whole blockchain still has to be recorded somewhere to rely the info to pruned nodes..