:) It is most definitely not a scam. HEAT has assets which are certified and backed by the company HEAT Ledger Ltd, labeled as 'certified' and with a green check mark.
You are mistaken. On the assets you refer to, there are massive yellow banners, as well as a red X under certified on those assets which say: "CAUTION: This market comprises unverified asset from 3rd party outside the scope of Heat Ledger Ltd redemption gateway." You can see this yourself by going to the exchange on the webwallet.
These assets have been created by unknown users who paid a fee to the network to create an asset. It is a public decentralized network, so anyone can create an asset. This is why there is certification, as well as massive bright yellow warnings on these assets.
In the pipeline is to make crypto assets the real coins being traded, a true multi-wallet & DEX. Also there are 20+ crypto assets created but not listed in the market yet, which will be also certified assets.
There are also some released images of a totally fresh UI which is already completed and was demonstrated at some events. Also microservices will soon be integrated into the mainnet. If you thought 'smart-contracts' were neat, you should read what microservices are about:
RE: Why we need Decentralised Exchanges