A fixed fleece liner means the soft, fuzzy inner lining is permanently sewn into the glove. It gives you a comfortable feel against your skin and wicks away sweat during a day on the slopes.
The big advantage is simplicity—there are no separate pieces to lose or keep track of, and the glove feels cohesive right out of the box. Fixed fleece liners are a solid choice for everyday resort skiing and day trips where you can hang your gloves to dry at the end of the day.
The trade-off is that you can't remove the liner for faster drying or washing. If your gloves get soaked, they'll take longer to dry overnight compared to gloves with removable liners. For multi-day trips or backcountry touring where quick drying matters, you might want to look at removable liner options instead.