A couple of points jump to mind:
This is probably why most people make this decision.
Cross country skis are a lot more expensive than snow shoes. So if you’re not actually planning on skiing you wouldn’t buy skis!
You need to be able to ski to use CC skis; to use snow shoes you just need to be able to walk! :)
Generally (though this depends on the make/model) snow shoes can cope with steeper ground than skis. I’ve certainly seen videos with CC skiers using snow shows (coupled with crampons) to ascend very steep terrain even though they’re carrying skis.
Skis are a lot faster than snow shoes. You can ski up a reasonable slope a lot faster than in snow shoes. Snowshoes are bulky and awkward to walk in.
In skis you can ski down (!) in snowshoes you have to walk. :( This is obviously disadvantageous to the shoes.
This is quite variable, but big snow shoes (those with a large profile) can enable you to walk though deep powder where CC skis would struggle.