  Scalability has been a bottleneck for major blockchains such as Bitcoin and
Ethereum. Despite the significantly improved scalability claimed by several
high--profile blockchain projects, there has been little effort to understand
how their transactional throughput is being used. In this paper, we examine
recent network traffic of three major high-scalability blockchains--EOSIO,
Tezos and XRP Ledger (XRPL)--over a period of seven months. Our analysis
reveals that only a small fraction of the transactions are used for value
transfer purposes. In particular, 96% of the transactions on EOSIO were
triggered by the airdrop of a currently valueless token; on Tezos, 76% of
throughput was used for maintaining consensus; and over 94% of transactions on
XRPL carried no economic value. We also identify a persisting airdrop on EOSIO
as a DoS attack and detect a two-month-long spam attack on XRPL. The paper
explores the different designs of the three blockchains and sheds light on how
they could shape user behavior.
