Maybe to manage expectations and make it clear it was a spin-off not a full-fledged Tomb Raider experience. I remember having a fun co-op experience with Guardian of Light. The character packs that replaced the main characters with characters from other Eidos games were a bit amusing. I also enjoyed Lara Croft Go, it was a neat little puzzle game alongside Hitman Go, I wish Deus Ex Go had also received a proper port to pc or consoles.