Many people bought the Kailh/Novelkeys Cream switches because, well, they just sound smooth. They are made with POM, a supposedly "self-lubricating" plastic, which was supposed to make it very smooth. These were a decently popular linear switch.
Then, Taeha Types, the foremost keyboard content creator, created a video where he built Tfue, 2019's top streamer, a custom $3000 keyboard where he used Novelkeys Creams. This brought a lot of attention to the switch, especially considering that it was $45 for 70 of them, a fairly reasonable price. This started the Novelkeys Cream hype train, which I admittedly joined. I bought some of these, and here are my thoughts.
Obviously the first thing that comes to your mind when thinking of these switches is the smoothness. However, "self-lubricating plastic" is a bit of a misleading term because the switch only releases microscopic amounts of teflon. When the switches are stock, they are actually... bad. They are quite scratchy, honestly comparable to Cherry MX Reds. Considering the medium $45 you are paying for them, this is disappointing and I highly recommend that you lubricate them. Once lubricated, they are very smooth, although still beaten out by Gateron Ink or Gateron Optical switches.
This is an area where the Novelkeys Creams excel. They have very tight housings, so there is no need to film them. Additionally, the fit between the stem and housing is very snug. This is one area where Gateron Optical switches are weaker in.
When you use the switches stock, the sound is pretty good, and there is barely any ping from the switches. However, when matched with an isolation-mount keyboard and lubed properly, they have a beautiful tapping sound. Lubed, they sound pretty good in any keyboard honestly. Here is an example of Novelkeys Creams used to create a deeper sound.
This is a very solid linear switch, after lubrication. Before lubrication, I wouldn't buy it considering that it's twice the price of Gateron Reds or MX Reds, but after lubrication it is up there with the best of them. Especially if you want great sound, the Novelkeys Cream is a very solid switch.