Removable fleece liners are a great choice if you ski multiple days in a row or deal with changing conditions. The biggest advantage is that you can pull the liner out at the end of the day so it dries much faster than a fixed liner—sweaty gloves that don't dry overnight are a recipe for cold hands the next morning.
Another bonus is versatility. On warm spring days, you can wear just the liner by itself for a lightweight, comfortable feel on the slopes. When temperatures drop, pair the liner with the shell for full warmth and weather protection.
The tradeoff is that removable liners add a bit of complexity—you're dealing with two separate pieces that can shift around slightly while riding. They also cost a bit more than fixed-liner gloves. But if you're doing multi-day trips, backcountry tours where you're working up a sweat, or you just hate putting on damp gloves, the convenience and drying speed of a removable fleece liner is absolutely worth it.