Me not thinks HashGraph is like IOTA because that only does 100 TPS and HashGraph is more
like 50,000 TPS or something
EOS and Cardano scale into hundreds of thousands per second. IOTA is just "slow at 100tps" because it scales with the size of the network, which isn't big now. But should IOTA make good on their promises and become the payment system for all things IOT, we would easily see millions of transactions per second. (I think Cardano also falls into that category)
Regarding how it replicates data,as I understand it its kind of like Anycast traffic (you can can google that) where it is "one to closest". But this replication is just a transaction as far as I know, then follows a round of pseudo voting. The timestamps are sort of like blocks. I don't think that all transactions are held in a database by all nodes in the hashgraph network though.
Modern blockchain projects still beat this hashgraph by far, but they are aiming at selling solutions to business. This means its meant for an entirely different use case and it is an entirely different technology.
Its cool that it exists, I am sure Swirls will do well with their product, but it wont replace BTC, its different things. Its like comparing Visa transactions to a home loan - different things.