Scissor switches are mostly seen in laptops. They have a low profile design and are made to be bottomed out to actuate. They are a variation of the Membrane Switch Technology that was introduced in the mid to late 90s.
As its name suggests, there is a scissoring mechanism found inside a switch. Once it closes, the switch actuates. This is considerably different from mechanical key switches since those require two metal points to meet before the switch actuates.
In addition, mechanical keyboards have different actuation points depending on the type and model of switch used. Some switches need to be bottomed out, while others have a higher actuation point. Scissor switches, in contrast, will generally feel the same regardless of the model of the keyboard.
The mechanism of scissor switches may initially seem bad since they needed to be bottomed out. However, when you consider that the travel distance of these switches is low, you will realize that they are actually very efficient.
The lower profile keys that most scissor switches have been preferred by some users and allow them to type or input commands faster. In addition, they significantly make less noise than membrane, rubber dome, or mechanical keyboards.
And lastly, scissor switches have no issues in terms of stability. They have no key wobble, and there is no risk of the keys getting detached while in use.