Boofing is neat and all, but it's in many ways more of a pain. You have to do it in private, or risk exposing "too much".

Taking a bump is really discrete, and basically all of the associated paraphernalia has valid excuses (straws are things people often carry on them, stuff for making lines can look just like a business card, and nasal sprays, whether for getting drugs up there or clearing out the nose after).

Injecting isn't great for your health by any measure, but you don't have to remove much clothing. There is also valid reasons to be injecting (like HRT), though even in legit cases people will probably suspect drugs. With injecting, it's really easy to see what you're doing, and if it's just IM you don't even need to be picky. Tie-offs might seem like a pain, but they're really not that bad.

Boofing probably beats out smoking though. Thanks to the distinct smells, smoking is really hard to hide. Crack and meth smell nothing like nicotine or weed. Smoking hardware is usually more expensive than the oral needle that's most commonly used for boofing. Boofing is easier to dose out, still quick acting (while being relatively long lasting), doesn't come with lung issues, and it usually doesn't ruin potency the way oral can.

But you're right, boofing is a bit overlooked. I think it's because there is a strong lack of literature (psychonautwiki for example doesn't seem to list numbers for boofing), and because there isn't really any legal use-case (DIY boofing and suppositories aren't that similar).