So you will be rewarded by doing transactions. I forgot where did I heard this idea from another project. But it's not called Proof of transaction. So you're the first to coin this word I think. I thought there's no ICO but when I checked the website 74% will be allocated. Would it be too big if you're thinking of the number of transaction and not the volume?
If i understand your question correctly, here is the answer, We use mining club accumulated transaction fee as weight to give probaility for next block generation. We plan to use transaction numbers to replace time interval. Our ICO is for two purpose: 1. Keep lights on in TAU foundation. 2. Distribute TAU coins to massive public by 1 million TAU auction in EOS style daily from Oct 15th. Once TAU reached equliblium with BTC, we will end ICO and do pure bounty program.