Define/Explain src and srcset
Src is the default source that an image is pulled from to show to a user. Srcset can be used to choose a different size of an image to show depending on the user's device. For example, if you wanted an image with a smaller size to show on a mobile device instead of an image with a larger size, this attribute would be able to help with that.
Define/Explain sizes
Image sizes are important because one photo size may work well for a device that someone is viewing with, but may not work well for another device. A photo may need to be cropped for certain devices to fit well. For all devices, it is generally good if images can be high quality, but not too large pixel-wise for a quick load time as well.
Explain why art direction
Art direction is important for design purposes and it is very important that a website is designed with a goal in mind. Art direction makes sure that goal is achieved with a design that communicates the message to the user.
Summary
Overall, the srcset attribute can definitely be helpful when images are not fitting well on a certain device. This can be very useful when it comes to art direction so that the website design still clearly communicates a message to the user.