h6 is a blessing and a curse

The pawn on h6 (or h3) can be both a blessing and a curse. While it provides some breathing room for the castled king, and annoys adventurous bishops, in is often a target for sacrificial attacks. Many juniors (include myself when I was younger), hoped to line up the bishop and queen on the c1-h6 diagonal and blow open the kingside with Bxh6.
Older and more experienced players normally deal with such obvious threats, but sometimes the sacrifice is underestimated. Whether David Howell saw the threat and decided it didn't work, or simply thought Gawain Jones could not play it, is unknown to me, but the fact that it was played resulted in a very entertaining game. Objectively the sacrifice wasn't winning, but it gave Jones enough play that eventually Howell was unable to defend all the squares around the king, allowing Jones to win back the sacrificed piece. After that is was a matter of harassing the exposed king until a winning simplification could be played.

Jones,Gawain C B (2682) - Howell,David W L (2696) [C50]
ch-GBR KO 2018 London ENG (3.2), 12.12.2018

1. e4 e5 2. Nf3 Nc6 3. Bc4 Bc5 4. O-O Nf6 5. d3 d6 6. c3 a5 7. Re1 h6 8. Nbd2 O-O 9. Nf1 Ne7 10. Ng3 Ng6 11. h3 a4 12. d4 exd4 13. Nxd4 Re8 14. Be3 Bb6 15. Qc2 d5 16. exd5 Nxd5 17. Bxh6 Rxe1+ 18. Rxe1 Bxd4 19. cxd4 gxh6 20. Nh5 Ngf4 21. Re5 Be6 22. Qc1 Nxh5 23. Rxh5 Nf6 24. Rxh6 Ra5 25. Bxe6 fxe6 26. Rg6+ Kf7 27. Qh6 e5 28. g4 exd4 29. g5 Rf5 30. gxf6 Rxf6 31. Qh7+ Ke6 32. Rg8 Qd7 33. Rg7 Qc6 34. Rxc7 Qb6 35. Rxb7 Qc6 36. Rc7 Qb6 37. Qe4+ Kd6 38. Rc4 d3 39. Rd4+ Kc7 40. Qe7+ Kc8 41. Rc4+ Rc6 42. Qe8+ Kc7 43. Rxc6+ Qxc6 44. Qxc6+ Kxc6 45. Kf1 1-0