There's a benefit to having multiple platforms on your development team if you are developing something for multiple platforms.

It's too often I see projects with "supports Linux, OSX, and Windows" only to find that none of the maintainers actually own a Mac and therefore it is filled with bugs and often requires the user to "find their own dependencies".

If we are talking days of time and not weeks, the benefits of making (and keeping) your whole system cross platform could pay off big time in the future when you or someone on your team wants to switch, or you just want to easily test on other platforms.