A 1×12 setup (one chainring up front, 12 gears on the rear cassette) isn't just for gravel anymore — it's a legitimate choice for certain road riders. The biggest advantage is simplicity: you only shift with one hand, there's no front derailleur to adjust or drop the chain from, and the handlebar area looks cleaner without the extra shifter and cable.
The trade-off is that the jumps between gears are larger than on a 2× system, so you may not always find that perfect cadence. Also, strong riders who like to push big gears at high speeds might find the top end limited compared to a traditional 2×12 with a large chainring.
1×12 makes the most sense if you ride all-road routes with mixed surfaces, if you find front shifting frustrating, or if you simply prefer a less complicated bike. For pure road racing or fast group rides, a 2×12 still gives you tighter gear steps and a higher top speed.