Assuming that both databases are Oracle, both run relatively recent versions of Oracle, and your organization has administrative access to both systems ("core banking" databases are often run by third parties), Streams is a more efficient architecture than materialized views on the capture side (assuming that you are doing incremental refreshes with materialized views). It's more work to configure than materialized views but you get much greater flexibility and better performance.
Oracle's direction is to move away from Streams and towards GoldenGate which requires additional licenses. Since Oracle does not plan on enhancing Streams moving forward, if this is a strategic decision for your organization, you might want to look at GoldenGate instead even if it doesn't offer any benefits today over Streams.
As i und from your words, streams is more efficient way. Also i should say this also, this synchronizing proccess should be run as much as often. Like every 5 min or less. I mean tables should be synchronized every 5 min. Streams is also useful for this strategy?
Streams can generally keep the lag between a change being made on the source system and that change being applied to the destination system to a few seconds (assuming, of course, that you have sufficient hardware resources). Keeping the lag to a few minutes shouldn't generally be a problem.