Slot machines used to fill casino floors in bulky cabinets over 40 inches tall....

https://lorenzosnewblogs.nexorafield.com/posts/why-do-mobile-slots-need-bigger-buttons-than-you-expect

Slot machines used to fill casino floors in bulky cabinets over 40 inches tall. Now they easily fit in the palm of your hand on screens around 6 inches wide. This shift shows how technology has shrunken big machines into portable fun you can play anywhere