If it is used and effective depends on both the players and the DM.
Generally newer players who have been lulled in by the Combat as Sports philosophy don't recognize the power of the hut and only use it for its advertised function.
But the people who recognize it sometimes start spamming it, its free after all, which is especially effective when the DM runs a dynamic dungeon instead of having the monsters wait in their rooms for the PCs to arrive to slaughter them.
I agree with monsters not being static piles of stats waiting to be slaughtered.
Come to a crossroad? Create a hut and depending on the architecture you have split the enemies forces in half.
Not sure what kind of campaign you run, I admit I don't use old school dungeons so this would never happen in my game. There will almost always be a back door or way to get around a single choke point.
But I
always found the "traditional" dungeon kind of silly unless it's something carved out of a natural formation. Why would anyone dig out tons of rocks just to create hallways?
In my games, the enemy would either use an alternate route or make one by knocking down a wall or two.
A suspicious sarcophagus? Create a hut and the open it. A trap? Create a hut before attempting to disable it.
Or have the trickster rogue disarm the trap with mage hand or the party hides around the corner. I don't see why this is an issue. If the undead creature released from the sarcophagus is at all intelligent they'll just go behind cover or leave.
In some cases the PCs might even succeed in creating a hut right before the room of the BBEG although that likely requires some setup and the real spell instead of a ritual and now have a bunker to retreat to and depending on the layout force the enemy to abandon his position unless he wants to be shot at from inside the hut.
It takes 10 minutes to cast. What's the BBEG doing while they're casting? Most fights are over in a minute or two at most. What's stopping them from just retreating behind cover and waiting out the PCs?
The hut is also very useful for Helms Deep type scenarios. Orks break down the door? Cast a hut right behind the door. Not only did the orcs achieve nothing, you can now freely attack the orcs unless they have dispell magic forcing them to retreat and letting you repair the door.
And especially in such scenarios where you have a long time to prepare you can set up multiple huts to make dispelling them less effective. I still have an open argument about if you can create a hut inside a hut to have multiple layers.
I think the Helm's Deep scenario is legitimate only because of how movies depict sieges. Most castles were traditionally pretty impenetrable without siege engines. But showing how the enemy army camps outside the keep for months at a time in order to starve out people is boring. If somehow the PCs have a hut 24X7 and access to create food/water then the enemy would bring in the trebuchets and bury the hut. Might take a few days, but most sieges lasted for months.
But think about that scenario. They weren't facing a few dozen orcs, they were facing hundreds if not thousands of orcs with a handful of defenders. Orcs that were willing to throw their lives away. In that scenario in my campaign the hut would have just been covered in bodies after a bit (or use a different tactic).
If an army is invading, there are many, many options to counter the hut that I covered in my first post.