Except you don't want the access time found on spec sheets and generic benchmark results but effective access time, the kind that's subject to caching, contention and the location of the data on the drive.
This is true, but in general a drive with a faster access time will be faster at these kinds of tasks. Lots of variables at play of course.
What is source code doing on the hard drive to begin with?
If he's just developing at home or working on local checkout then this is reasonable. Setting up a source control server may be a bit overkill for some home uses.
Someone at work (not me) ordered a bunch of PCs for our developers without checking the specs first and they came with WD green drives. Source control checkin/checkouts and compiling are downright painful on those drives. While SSDs are awesome for this task, even standard 7200 RPM drives made a huge difference.