A decisive difference is the walking mechanism to enable hiking. Once activated, the shaft can be moved forwards and backwards to allow the walking movement. Once at the summit, the mechanism is locked and the shaft is fixed for the descent. Ski touring boots are lighter than alpine boots, so you have less weight to carry uphill. And: the lighter the boot, the smoother it is on the ascent (like the Dalbello Quantum, for example). If you focus on dynamic downhill descents, you need a "more stable”, somewhat heavier boots for high power transmission, such as the Lupo series from Dalbello. They are the perfect allrounders for an extremely wide range of use and, thanks to the pre-mounted GripWalk sole, can even be used with alpine skis (with a GripWalk binding).
Alpine touring boots have a robust rubber sole with a profile similar to a mountain boot and, unlike the alpine boot, are certified according to a different standards (this specifies, among other things, other sole dimensions). Therefore it is normally not possible to use a piste binding with a touring boot. In addition to alpine ski boots (ISO 5355) and touring ski boots (ISO 9523), there are “hybrid models” that overlap. These include GripWalk boots, for example. In addition, many ski bindings can be adjusted on the toe piece to accommodate both touring, alpine and GripWalk boots (e.g. thanks to Sole.ID). Rubber soles are more suitable because they have a dampening function and offer better grip and also allow that rolling feeling of the foot. Most touring ski boots now have so-called pin inserts on the tip of the boot, which serve as holding points for the toe of pin bindings. Many pin bindings also require special inserts at the heel.