Are .bmp files really that bad?

[Carrie Baker]

I was out of the office for a few months and someone else updated the
user guides I work on.
I found that all of the screen captures they made were .bmp files.
I work on FrameMaker with referenced graphics, we convert to PDF which
are distributed both on a CD and over the internet and we create
WinHelp files.
I generally use a .gif or .png format.
When I am given .bmp files I convert them to one of those formats.

But is .bmp that bad?
Is there any reason that I should convert the .bmp files I have now to
.png (will it affect the project, or PDF in anyway?) or should  I
leave them as they are?
thanks
-- 
Carrie Baker
carriebak at gmail.com