Semi-dedicated VPS vs VPS

Hi there, that's actually a great question.

The biggest difference is that you do not gain root access, so customer websites do have to conform to our standard configuration. There are also stricter limits on things such as php execution timers and php memory limits.

If you need something like say redis, memcached, elastic search etc for websites then a VPS is the route to go as it is much more customizable.
This confused me too. Wouldn't that make it a semi-VPS rather than a semi-dedicated? As it's a step below a VPS and not a step below a dedicated server?