Strike allows you to deposit cash and buy bitcoin. You can send the Bitcoin to anyone instantly using the lightning network. You can also send a lightning payment and receive cash in your bank.
This means you can use Strike to fund lightning-integrated exchanges with bitcoin instantly or to make instant lightning payments.
The Lightning Network is built as a second layer above the Bitcoin base chain to facilitate fast transactions with low fees. Bitcoin is the currency used in both, but Lightning transactions are often denominated in satoshis (one hundred millionths of a single bitcoin).
A number of exchanges have announced support for the Lightning Network in recent weeks, including OKCoin, Kraken, Bitfinex, and Bitstamp.
Strike is currently only offered in the United States and only supports the US dollar. It is currently not available in New York and Hawaii.