In contrast to his incarnation being the worst hero in the game and one of the worst card designs for the Hobbit trait, Pippin is one of the best designs for the trait. How do Hobbits work? They engage enemies with high engagement costs and gain benefits as a result, just as in the stories the Hobbits have a habit of rising to the occasion when they take on tasks most would deem too big for them. And in this regard, Pippin gives you one of the simplest benefits you could get - engage an enemy with engagement cost above your threat, draw a card. On top of that, he increases enemy engagement costs making it more likely you can trigger that card draw (incidentally, that's something which might've helped Pippin, if his ability scaled somehow depending on how many Hobbits you had instead of just only working with all Hobbits). This is simple design, and that's one of the reasons it's so good. You buy The Black Riders for the first time, open it to look at the player cards eager to see how Hobbit decks are going to work, and immediately on looking at Pippin and Sam Gamgee you can see at a glance how the whole archetype is intended to play. Those two heroes by themselves define the playstyle of the standard Hobbit deck and clearly communicate it to the player.
Of course, as I've already alluded to, one of Pippin's strengths in stark contrast to Pippin is that he still works without needing to be stuck into a dedicated Hobbit deck - even with no other Hobbits, he still increases engagement costs by 1 as well as keeping your threat low with his starting 6, meaning you stand pretty good chances of using him as a draw engine. He's a great glue hero, who you can just drop into a deck and pretty much know he's going to be useful. In addition to Hobbits he pairs well with Dunedain, since they also like engaging enemies, and Rangers (who sometimes overlap with Dunedain), since they sometimes like engaging enemies (Faramir, Mablung) and since natural if niche partner cards Take No Notice and In the Shadows count Hobbits and Rangers both.
In a Hobbit context, Pippin plays perfectly with the archetype - in fact he and Sam baically define the archetype even with no other support cards. In a non-Hobbit context, he's still likely to be incredibly useful just by himself, and can function as an excellent glue hero to make the rest of your deck run smoother.