Sure, fitting everything in a carry-on is handy, but not everyone can do that. Some meetings need extra gear like product samples or tech gear. Checking a bag might be the only way to bring what you need. It's not about being inefficient, it's about being prepared. I always try to pack light, but I get why others can't.
Totally get what @beth_mitchell is saying. Sometimes you need that checked bag for demo gear or extra cables, it just is what it is. What kind of stuff usually forces you to check a bag?
Wait you guys are bringing product samples on planes? That's wild to me, I'd be so stressed about them getting lost. My whole job fits in a tool bag, I can't imagine having to check that stuff.