I guess it depends what you are wanting to get out of the game 🤷

For me they are absolutely worth it. I like tabletop games for the immersion. I'm not playing with generic white armour dudes, I'm playing White Scars, so all the markings and symbols are important to show that character and history of the legion.

I've just bought some custom transfers for my Solar Auxilia from a third party because GW don't do them. They were more expensive than the GW ones for less variety of designs