That conflicts with their statement being both TBC and WotLK. Wraths exp gets cleaved hard, like 50%. But TBC is nearly unchanged from WotLK levels, you’d honestly save maybe 5% of your time there in Cata compared to now. I’d hardly advertise that as accelerated.
I did 1-80 on the beta. You sail through 1-60, get bogged down INSANELY bad by TBC then fly right through WotLK afterward. TBC stands out like a sore thumb, it’s an awful middle swamp of molasses in the leveling experience. It’s basically classic era quest design, slow as hell, low drop rates on lots of quests, tons of running around, etc. Sandwiched in between Cata revamp style super efficient quest design and Wrath decently efficient quest design. It STILL suffers from this to this day inr etail, you can Chromie Time level through any expansion and TBC feels absolutely horrendous compared to every single other option. People are best off dungeon spamming past it even if they don’t like dungeon spamming.