Thanks for checking out Coinage.fund, LeGaulois!
I tried the demo and wasn't able to find the section to place the trades. Or does the site only collect data from the connected accounts and perform no trading actions?
The service does perform trading actions on your behalf. When you register you'll be asked how many of the top cryptocurrencies (ranked by market-cap) that you want to hold. Coinage will then continually monitor your exchange accounts and place any trades needed to make sure you are always holding the right amount of coins, in the right weightings (based on current market capitalizations).
When logged in to the demo account, you can click "Change index" to see how this choice is made, or go to this direct link:
https://Coinage.fund/#allocationFree users have not the Multi-exchange feature, so what they could do on the site?
Free users can connect a single exchange account (either Binance or Bittrex) and have their assets in that account balanced. Paying users can connect multiple accounts and "spread" their assets between multiple exchanges (the thinking is that people who have a higher value portfolio may be more concerned with minimizing losses in the event of a single exchange failure).
Does this answer your questions? I'd be happy to elaborate or answer any other questions!