Optimized vs Proxy for slower laptop

Were sending our creative director off with an older MacBook Pro and some footage she needs to organize in events and rough edit while gone. There isn't an issue with disk space but would like to keep the project on the internal drive. Would it be kinder to the system to load the laptop with optimized footage or Proxy footage? There's room for either and edits will be limited to putting clips in timeline with no transitions or compound clips.

Optimized footage is basically lossless prores 422 files so they are more edit friendly but still can be quite large. Proxy files are the much smaller low resolution files and are more easily manageable on slower systems. If you don't need to apply transitions, color correct or otherwise see full resolution images on your timeline, then use the PROXY files.
You can transcode them later before exporting back to original or optimized footage files.

Transistions and such can be used with Proxy footage, absolutely. There's no need to transcode "later" to get back to original files.

You'll ingest telling FCPX to Optimize only if it's not already a QT .mov file already.

Also tell it to create Proxy media.

In Preferences change Playback from Original/Optimized to Proxy. And Playback quality to Better Performance.

When you're ready to color correct and export, switch the Preference for playback from Proxy to Original/Optimized. FCP X will then point to the original/optimized files for full res output.

But you can't transcoded from proxy back to full rez.