Still, there have been many other "Time Walk" variety cards printed over the years, including the ever-popular Temporal Mastery (5UU) from Avacyn Restored. Beacon of Tomorrows (6UU) from Fifth Dawn even was reusable - shuffling itself back into the deck after use. There's also Time Stretch from Tenth Edition which let you take two extra turns for 10 mana (8UU - 8 and 2 Blue).
That's right: If you have 8 cards in your graveyard, you can take an extra turn for only 3 Blue Mana (UUU). This is an extremely attainable thing to do, especially in Mono-Blue or predominantly Blue decks that use a lot of instants and sorceries as part of their control schemes. This card becomes extremely valuable late-game, when an extra turn can simply finish the game.
Exiling itself after use does prevent Temporal Trespass from being too horribly broken, but this doesn't mean that its effect can't be copied while it's still on the stack. Duplication effects can still take good advantage of this card. Still, it's just a bit too pricey for most Constructed formats, even if it can often be 5 or fewer mana to cast.
Now, Commander probably didn't need another extra turn giving card. But since it exists, Commander deck builders are happy to try and use Temporal Trespass
to its maximum potential. Narset, Enlightened Master is happy to cheat it into play for free, and Jhoira of the Ghitu is happy to suspend it for just 2 mana. Many Commander decks have found a home for this card, and it's really the only format in which it sees much play.
The Wizards design team did a good job with this card, making sure that it wasn't too broken. Treasure Cruise and Dig Through Time were delve cards that proved to be a bit too powerful for most formats. Compared to those two, Temporal Trespass is going to feel underwhelming, but as Delve cards go, this is a perfectly useful and playable one, at least in Commander.