I see it as the most important home maintenance tool. Saves hundreds per year on little things that break. Like a wall patch, small o-ring for a toy, drawer slide mount, basement light mount, etc. I will say though that the learning curve is a bit rough if you don’t have CAD experience.
I built a four-poster bed, and 3D printed the fittings for the curtain rails and the attachment point for the fan.
I built a desk, and 3D printed the entire shelving system for it.
I designed and 3D printed an entire range of boardgaming accessories (storage bins, dice towers, meeples, etc)
I only bought the thing as something to do while in COVID lockdown. But it's been really useful.