One of the main advantages for using dark mode on a website is that it reduces strain on the eyes. Other advantages of using a dark mode theme are that it can give a better aesthetic look, help improve user focus, and prolongs the battery life of a device.
One of the main disadvantages for using dark mode on a website is that it can result in design inconsistencies. For example, images and videos with various backgrounds may not blend as well with the dark theme. And although dark mode can improve users experience for some, it may cause problems for those who suffer from low contrast sensitivity and astigmatism. It can also cause a "halation" effect in which the text appears to have a halo or blur, making it difficult to read.