The climb restriction is there to protect from traffic on other SIDS.
The speed restriction is there to enable you to fly the SID track without overshooting the turns and conflicting with otherwise separated SIDS.
Two different things entirely.
p.s. please don't ASSUME that climb is unrestricted ( as many SJ based pilots seem to be doing these days - reading back "unrestricted" regardless of whether or not it was included in the original instruction) - if the restriction CAN be cancelled, it will be.