A majority of the unique addresses belongs to depositors instead of withdrawals.
Given that Optimism is an upcoming L2 blockchain on Ethereum, this is an encouraging trend!

Lastly, the peak in bridgoors at the start of Jun is likely in relation to the launch of the OP token Airdrop #1!

Here's a couple of stats that provides an overview of the bridging transactions undertaken by all the users over the past 60 days.