Very nice items and worth using. In France, giving a set of fine steak knives or if lucky a canteen of really good tableware are still items given as wedding presents, high quality table-ware is still appreciated there, part of the meal.Many look like fixed Laguioles or other patterns and are decorative.
I would not think these are Ivory though. Ivory has always been expensive- even when millions of Elephant roamed the world, it is very fragile and liable to cracking and warping with extremes of humidity, thus it is not really that suitable for table-ware. It can be found on Fruit table knives, more commonly MOP, on certain serving items such as Fish knife&server and would've been kept in its own Morocco leather case after careful washing. I've seen it as inlays on Silver teapot handles- Silver conducts heat very well and the Ivory segments were not only an ornament but as a kind of 'washer' to stop the handles getting too hot.
The c19th and c20th saw huge changes in tableware, mass-production and machine made blades made them affordable reliable and durable. The advent of stainless enhanced this as cleaning and drying large quantities of non stainless knives was a chore for hapless servants in big houses or in restaurants/hotels. There were knife polishing machines for this purpose but like hand powered coffee grinders a thankless task.

Handle types were Sterling Silver, EPNS, Bone, Woods, early plastics,Rubber, Cell, the latter being popular in England at least, French Ivory as others have remarked. And it's thankfully durable compared to other Cell you can find on fancy pocket-knives.
I'd use them for special occasions , why not? Keep them out of prolonged light and look out for a box-canteen to keep them in, usually felt lined with divisions for various types etc.