the terminology is "serrated edge", "combo edge" and "plain edge", frequently abbreviated as SE, CE and PE.
Long ago I was buying combo edges and I believed the common wisdom that the combo edge was useful for cutting certain things and the combo edge was the best of both worlds. Well now almost 20 years later I've realized that in all that time I never actually cut anything with the serrated part of the edge. So now I mainly buy plain edge knives and don't buy combo edges except in unusual circumstances. I will not even consider buying a knife with CE blade unless it is a rare discontinued knife that I only find in CE version, such as the Benchmade Ares that I recently got.
But I did recently buy a full serrated edge knife to carry as a second knife, thinking if I ever had to cut something that was appropriate for the serrated edge I could use it. I carried it some but never found a serious use for it. Shortly after buying that one I bought a SE Spyderco Ladybug. I was showing it to my daughter one day while we were having lunch at a fast food restaurant, and was also carrying a PE Spyderco Tenacious with sharp factory edge. So I took a paper napkin from the dispenser on the table, rolled it up tightly, and had my daughter cut it with the Ladybug while I held it stretched between my hands. Then we did the same test with the plain edge Tenacious, and it cut through the napkin faster. This was not a fully scientific test because the serrations on the ladybug are fairly small and not representative of other SE knives. I should try it with my SE Byrd Hawkbill.
When I first started buying "modern" knives, CE blades were probably more common. Now I would say that while there are still a lot of CE knives made, I think they are a smaller percentage of the total than they were many years ago.