From Vlad’s end, an extension also makes sense as it probably gets him to his “FA years” a year earlier.
Assuming no extension, we would probably start Vlad’s clock in mid-April 2019. I think that this gets him to FA by 2026.
Signing him to an extension now gets him to his FA years in 2025 - 1 year earlier.
From his point of view, I think that three years’ worth of options should only be thought of as two additional year under contract, making it more appealing.