The purpose of the
start-pulseaudio-x11 scripts is to integrate Pulseaudio with Phonon.
Of course will Phonon will also run and play sounds without Pulseaudio but applications that rely on a functional Pulseaudio sound server will not be able to run then. This will also be true for devices that are loaded by Pulseaudio rather than with Phonon.
Below are two examples to illustrate the difference:
Note that only in the first instance we will have access to audio devices as defined by a pulseaudio module. In this case this is the internal sound card, and an attached Airport Express. In the second instance we will only see the "Pulseaudio Sound Server" which can not further be controled.
Still, pulseaudio will be loaded and will run in the background, and both scripts can be run later if we had not put them in autostart.
In case you do not need to control Pulseaudio with Phonon you are probably safe to delete the above scripts or their corresponding
.desktop files which will call these scripts but you will break the Pulseaudio integration with Phonon when doing so.
The delay issue when loading pulseaudio is related to a malfunction of module-x11-xsmp or of Avahi (see Pulseaudio Bug #58758). There is active effort to get this bug fixed, hopefully soon.