Here are some benefits:
– Faster load speed
– Small files and cache size
– Less demand on your web server
– Uses less bandwidth especially on mobile devices
These questions become second nature to you. However, other questions are not so obvious at first. Like, screen size. Do you remember when 640×480 was the gold standard in screen resolution? Then came 800×600, 1024×768, 1280×1024, etc.