In the past few generations, there has been a lot of complaining from fans about "random" types from Gamefreak.

Types in Pokémon are all ELEMENTS, even the ones that describe physical characteristics, like Bug, Dragon and Ghost. This is evidenced by things like the Plates, Gems, Hidden Power, Natural Gift, etc. These objects and berries are imbued with the essence of Pokémon types and their advantages. Hidden Power and moves like Dragon Pulse (which can be learned by non-Dragon Pokémon, for example) show that there's an "energy" to each power, that can be used by a variery of things. What is a Dragon Pulse? It's a pulse of "draconic" elemental energy.

Pokémon types just mean that a given Pokémon has as affinity and ease to use and control those elements, or has their energy running within them. What is Granbul? It's a "dog" Pokémon highly intimate with the Fairy element, just like Growlithe is a dog Pokémon of the Fire element. Of course, some elemental characteristics are easier to describe than others (like Fire, Water, etc) but they all have a set of symbolisms and a distinct flavor. Fairy is the playful/whimsical element (Play Rough, Mr. Mime) but it's also the "purity", "light" element (Gardevoir, Xerneas, Tapu Koko), and their designs draw inspiration from things like that, or even some malicious fairies like Mawile. Dragon, when it's not inspired by literal dragons or dragon-puns (like Mega Ampharos and Alolan Exeggutor), is the "legend", "power" type, the big mythical element, contrasted with the delicate and mysterious Fairy.

(cont.)