Dfat, as much as I respect you as a player, no. Just no.
You mention in your post a hat that is better than your swallow and that can't hit you back (D3).
Also, for ROB's, I will take his Dair's damage for that laser anyday. In 12 seconds you can get the damage back on him (assuming you fire the laser as soon as it is available every time).
I'm pretty sure Falco can't hit you, but again, the damage is given back in a matter of seconds. Snake? Same thing. Those grenades are so good I'd even eat a Fsmash for them if I thought I could survive it.
MK's hat is more useless than Inhale IMO...
Also, you forget Lucario (who can hit you after swallow, but it's worth it), Pika, Charizard/Ivysaur, Boozer, ZSS, Samus (if you ever fight one... lulz.), Mario, Wolf, DK, Ganon (no I'm kidding... DON'T EVER TAKE GANNON'S!), TL, Shiek, Fox, Pit, and Wario.
Wrong, everyone makes mistakes, especially if you have good mindgames. Running up to them and using inhale CAN work, especially if they shield/spotdodge because they're expecting something else.