You can use this Offerings to the doomed on your own Sacred Phoenix of Nephthys when he would be sent removed from the field without his effect being activated, like with the effect of Cyber Angel Dakini, Amazoness Onslaught. Allowing him to dodge your opponent's removal and return to activate his effect during your next standby phase.
You could use Offerings to the Doomed in a Spellbook deck as they already have amazing search power. The Grass Looks Greener variant of Spellbook decks also special summons most of its monsters from either the deck or hand. Meaning the Offering of the Doomed's drawback could not hurt your strategy that much.
I have this card, but will it be useful in my GB deck(don't comment on the GB deck itself)? Can it be useful as replacement for an Enemy controller as it destroys a face-up monster(which likely will attack a weak GB)?
I'm not sure why so many people underestimate Offerings. There is very little chainable removal at the moment, so this is fairly powerful right now. The only thing that holds it back, IMO, is not being able to destroy face-down monsters given how common Sylvans are.
Honestly, I can't see this being used all that much. For the decks that could actually use this effectively, I don't think they would have room for such a card that only destroys one face up monster. We'll see though, it could have use in decks that will be released in the future.
I prefer running spell that can get rid of spell/trap instead of monster since most of OTK deck already have monster removal such as Dakini and Marshaleaf.
Honestly I don't get why people is hitting on this card so bad. Its a quick-play which may have some potential in disrupting your opponent's play. E.g. Sylvan when they rose lover to Guardioak or Lotuswain pop them before they can even use their effect with this and thats one annoying card out of your way. Yes you might not draw after that but in decks like spellbooks or even like amazoness when you can search thing it won't matter that much.