A sofa or sectional on a patio without throw pillows looks like something waiting to be sold, not something anyone actually sits on. The pillows are what tell your eye this is a room, not a display. I didn't believe that until I put two plain cushions on a plain outdoor bench and watched it stop looking like a bus stop.
Where this sits well is anywhere you already have the bones of an outdoor room: a sectional, a couple of chairs angled toward each other, maybe a low table holding drinks. The pillows do the job indoor cushions do in a living room, they soften hard frames, pull colors from whatever is growing nearby, and give the whole setup a reason to look lived in rather than installed. As for wear, this is the part people get wrong. Good outdoor fabric fades a little over a season, evenly, which actually looks fine, but it does not love being left out through a real downpour or baking under full sun for months without a break. I learned to bring mine in whenever rain was forecast for more than an hour, because the first set I owned went moldy from the inside out and I didn't notice until it smelled like a gym bag. Covers zip off for washing, a hose and mild soap handles most spills, and shaking them out after a windy week keeps the fill from going lumpy. Treat them the way you'd treat a good beach towel, not a museum piece, and they'll hold up across a few summers.
This kind of setup earns its keep most in homes with a deck, porch, or patio that gets used for actual sitting, not just passing through, and it comes alive in that low golden light early evening, when the color of the cushions against the furniture is doing half the work of making the space feel finished. Spring and early fall are kindest to the fabric, full summer sun is the hardest season on color, and anyone with covered outdoor space will get far more years out of these than someone with furniture sitting exposed in open weather. Where it falls short is small balconies with no storage and no shelter, or climates with long, humid, wet seasons, since damp pillows left outside are a losing fight no matter how good the fabric claims to be. If you can't commit to bringing them in sometimes, skip it and stick with the bare furniture.
Add pillows to furniture you already own outside and the whole space reads like somewhere you'd choose to sit, not just somewhere you ended up.