I admit that I heard the term "nearfield monitor" for the first time when I read through all the material about home recording. "Monitor" in this context has nothing to do with a computer screen. It refers to monitoring sound and simply means "speaker" if you will. "Nearfield" stands for "they are really close to you".
Why Nearfield Monitors?
A home recording studio is usually small in space. You sit at a desk and the monitor speakers are quite close to you. So their "sweet spot" must be close too.
They also serve the purpose to most neutrally and honestly produce the sound that you have recorded. Using probably cheaper Hi-Fi speakers instead will not give you that accoustic honesty and would not be a good choice.
As it was with the audio interface, I had no experience with nearfield monitors. I could only judge what I read about them and the many reviews I watched.
Budget was another factor in my case and I opted for the JBL LSR 305 for about 100 euro per speaker. Based on customer reviews they are one of top products in their price range.