Looting, or the ability to draw a card and discard a card, is a perfectly fine ability. In fact, Jeskai Ascendancy allows you to do this whenever you cast a noncreature spell as one of its two effects. Card filtering is always cool to have. Ascendancy is particularly good alongside the Prodigy because whenever you cast a noncreature spell, not only do creatures you control get +1/+1 until end of turn, but they also untap, allowing you to then reuse the looter ability.
But there's another interesting thing about these Magic Origins flip-walkers that probably hasn't been talked about enough: once Vryn's Prodigy flips into Jace, Telepath Unbound, you can then go play another Vryn's Prodigy, because technically, they're no longer the same legend.
There's a big reason why this matters and it all has to do with Telepath Unbound's -3 ability. OK, we all knew that was good, in theory, as it basically gives you Snapcaster Mage's ability to give an instant or sorcery in your graveyard flashback. But it's a bit slower at sorcery speed. Still, it turns out that this combos really, really well with the Prowess mechanic and cards like Monastery Mentor and Seeker of the Way. Remember, even with flashback, you're still casting the spell, just from the graveyard.
Yes, it's not as good as Snapcaster Mage. However, if you happen to use the -3 ability, then flip another Vryn's Prodigy, you can sacrifice the copy you just used in favor of a new Telepath Unbound that can use the ability again in the same turn. There are many spells that Jeskai decks would like to use again, and you can use spells that you discarded earlier in the game.
For an investment of only two mana and having to wait a turn to use the loot ability, this planeswalker turned out to be a lot better than most previews anticipated. Getting 5 or more cards in your graveyard with fetch-lands and tons of cheap spells in the deck is not hard. So why was he so undervalued? His +1 is really meh, and planeswalkers are often judged by that first ability as much as their second. The ultimate also doesn't really excite people. Although milling your opponent five cards for each spell you cast is fine, when are you going to use his +1 ability enough times for it to matter?
That isn't to say you won't ever use his +1 ability, of course. That way you can realistically get two flashback triggers out of one copy of Telepath. Giving a creature -2/-0 in a format full of often pretty beefy creatures, though, is extremely underwhelming. It's far from useless, though.
Is Jace, Vryn's Prodigy and his flip-side going to continue to command a $30 USD price tag? Being a mythic rare that people want multiple copies of, even four in some cases, the demand alone will keep his price up.. For those that bought copies at $10-12 at pre-release, congratulations. You did very well for yourself. The hype on this guy likely will die down in coming months, unless he continues to post strong Standard results. I'd definitely hold the ones you have and watch his play in the format carefully. Remember that Vryn's Prodigy is only a 0/2, making him extremely fragile. But for only two-mana, his literal flip-side looks to be worth a lot more than most of us first thought.