If you care about security, don’t put a Sim card in your phone.
Depends on what you mean by security... or privacy. You need to define a threat model before any suggestions can be made.
If you're worried about someone hacking into your phone via an app, a sim card likely won't make a difference.
If you're worried about your location being tracked... that can often be done without a sim card or any cellular service on your device.
Then there are malicious carriers (or ones compelled by a government) that could track you without even having legitimate service activated. All phones at least in the US now are mandated to have (A)GPS receivers.
All depends on what your concerns are.
I don't think that comparison is fair because I explicitly said that people who wanted RT are already going out of their way to get things done. The average desktop user (putting GPS in every phone) won't benefit from it (or RT) and it could likely make their experience even worse.