Love the technology but having zero transaction fees is a misconception.

Nodes that want to make a transaction must first confirm two other transactions on the network.  In a sense they are 'mining' to process their own transaction.  Thus there is an electricity cost which can be seen as a fee.  Projects which need to make a large number of transactions end up racking up considerable operations costs.  Way better than bitcoin though because of the optimal nature of the tangle versus blockchain.