To add to what's already posted, using high res images will generally result in a large source file. So while a 100% vector logo could be 1 Mb or less, a logo including a high res image could quickly increase in size up to tens (?) or hundreds (?) of Mb.

Which could pose a problem when sharing this between different contractors as you can't just attach a large file via email and clients don't always have a routine in place for sharing branding assets from cloud backups.

I have worked with a lot of clients and many times they don't know where their logo is (after the logo being specifically delivered), or what format should be used for each task so including an image could add to this confusion on the client side.

To add to what's already posted, using high res images will generally result in a large source file. So while a 100% vector logo could be 1 Mb or less, a logo including a high res image could quickly increase in size up to tens (?) or hundreds (?) of Mb.

Which could pose a problem when sharing this between different contractors as you can't just attach a large file via email and clients don't always have a routine in place for sharing branding assets from cloud backups.

I have worked with a lot of clients and many times they don't know where their logo is (after the logo being explicitly delivered), or what format should be used for each task so including an image could add to this confusion on the client side.