A mortar and pestle are a duo of tools, when used together, can crush and mash things down. The mortar is the bowl part and the pestle is the club like tool used to crush items inside the mortar.

The usage of the mortar and pestle originally was use. It was used in Egypt thousands of years ago as a medical tool. Eventually, it started to be used as a tool for cooking as well. Bronze was the material of choice for creating the mortar and pestle around the middle ages and Renaissance period. Eventually porcelain was used by the late 1700’s. By the 18th and 19th centuries, a variation called a stone and muller was created to blend and mix paints. In India, another mortar and pestle variation was created and is called a sil batta. While having many different uses and variations, the mortar and pestle is mostly used today to grind spices. Another common use for it is to make a pesto sauce directly in the mortar and combine all the needed ingredients inside with the pestle. This tool has had so many contributions throughout history, culinary history included. While a very basic tool, a lot of people prefer it to more modern tools like food processors or grinders because it is believed this helps release aromatics better from spices and herbs. Whether true or not, many people still prefer a rustic tool as opposed to something that requires lots of disassembling of parts and washing. Whether you want to use a ceramic version to make pesto or guacamole, a marble one to crush spices, or a glass mortar and pestle to mix liquids, there is a variation for any culinary task at hand.

I believe the mortar and pestle is a significant culinary innovation due to how widely it was used all over the world for thousands of years before food processors were a common household tool. It is very traditional to be used to process spices and herbs in certain cultures as opposed to more modern tools too so that in itself shows how it is valued over things like mixers and food processors.
I believe the mortar and pestle accomplished being a culinary innovation from thousands of years of reliability. It is common for older tools and products to be overtaken by a more modern and convenient version. This is not the case for the mortar and pestle.
The mortar and pestle is important because it allows certain cultures to upkeep traditional practices for how they were taught on how to grind herbs and spices. It still allows people who would rather use it and not a food processor the ability to get a “feel” of how their ingredients are coming along as they get grounded.
The mortar and pestle is something that I have always found fascinating. I have used it to make simple things like guacamole and pesto sauce. I think it provides more control when crushing ingredients and it is just a nice alternative to more modern tools in general. I would compare it to the choice of use a gas or charcoal BBQ. Both are great and provide their own unique benefits but either could be argued as better or worse than the other. Having options in the kitchen is always a great thing.
References
Gritzer, D. (2019, March 05). The Best Mortars and Pestles To Buy. Retrieved from https://www.seriouseats.com/2018/08/best-mortars-and-pestles.html
Spices Inc. (2019, July 31). Retrieved from https://www.spicesinc.com/p-8344-the-history-of-the-mortar-and-pestle.aspx