Yes, if you want it to stay brown you'll have to oil it. How often depends on how much exposure it gets. Aside from that, ipe makes great outdoor furniture. It's sturdy and splinter-resistant.

I have an ipe outdoor furniture set and I strongly prefer the brown look over the silver weathered look. Would the furniture set still have caught your eye if the wood had been weathered silver instead of chocolate brown?

Mine sits on an uncovered roof deck in the northeast USA. I have to reoil it in the spring to maintain the look, but the results are well worth it. You may be able to get multiple seasons between reconditioning if it's not in direct sunlight.

To provide an idea of how the look changes throughout the year: The left photo shows the set when it was brand new in August 2020, and the middle photo shows it in January 2021. It hasn't gone silver, but it's lost some of its pop. The right photo shows it in May 2021 after I washed and reoiled it (unfortunately I only have this partial photo). I am reconditioning it for the 2022 season this weekend.