>>21080535I was quite fond of them for having infinite replay value and generally letting you do whatever the fuck you want with little to no story or railroading. Heck, just your first monster can potentially be one of hundreds of creatures.
Sure, some credits pop up the first time you get a monster to master rank, but there's really no end to the game and it just feels super comfy.
Though since Monster Rancher is extremely tedious, number-crunch intensive and entirely menu-based, so I can understand why it wasn't popular.