Siphon Insight
scryfall.com
{U}{B} • Instant • Look at the top two cards of target opponent's library. Exile one of them face down and put the other on the bottom of that library. You may look at and play the exiled card for as long as it remains exiled, and you may spend mana as though it were mana of any color to cast that spell. Flashback {1}{U}{B} • Innistrad: Midnight Hunt (MID) #241 • Illustrated by Livia Prima • Magic: The Gathering, MTG

[[Siphon Insight]]

It’s +1 card advantage for five mana by the time you’re done. You get a small amount of choice in what cards you take, but that benefit is counteracted somewhat by the risk that the cards on offer may not be synergistic with your own plan. As a mill effect it’s not very good, not that any of the decks I see playing it are trying to mill their opponents. The cards you siphon don’t count against your hand size, but that’s rarely relevant.

Wouldn’t [[Quick Study]] or [[Tainted Indulgence]] just be better?

I have a casual deck with [[Nashi, Moon Sage’s Scion]] so I absolutely understand the fun of beating someone with their own cards. That’s well and good for unranked games, but I’m seeing Siphon Insight in competitive decks in the ranked queue, where I assume most cards have to meet a higher bar than just “it’s fun”.

When someone plays SI against me I usually feel relieved. Better that than something impactful. I never bother to counter it (not that I’d typically counter small amounts of card-drawing anyway).

But am I missing something? Are you playing Siphon Insight in any of your decks, and if so, are you satisfied with it? What alternatives is it competing with and why is it better than them?