The problem is network disruption. Your system would work if you could guarantee all nodes in the network could communicate with each other every 10 minutes. What happens if this is not possible?

This scenario is called a netsplit in Bitcoin parlance. It has happened before, and it will happen again. In bitcoin, healing a netsplit is relatively easy, you pick the longest chain and you allow all the transactions from the smaller chains to be re-added to blocks in the new official chain.

In your system, if you had a double-spend where both sides ended up being accepted due to a netsplit, which one would win during the healing process? In bitcoin, the winner is the one that happens to be in the longest chain.

Secondly, how would you store the infocoin ledger in your system? The advantage of the bitcoin blockchain is that it provides an official source for all transactions that is easy to verify. A new node can come in, download the block chain and be certain they have all the information available about bitcoin ownership, with no holes. In your system, without a blockchain, how do you guarantee you have a record of all transactions, with no gaps?