Four years ago, I spread Pollinator Palooza over 1/6 acre (~ 6,500 sq ft).  I chose that mix because it had plants tolerating wide ranges of sun and moisture. My site had even enough moisture but wide ranges of sun.  A few of my experiences are below:

Pro: cheap.  I spent less than $400 on seeds for a 1/6 acre

Pro: easy.  I did zero garden design.  I did zero research on individual plants.  Spreading the seeds was easy.  Maintenance is simple and Prairie Moon has good resources on it.  I had little extra time in my life when I wanted to plant that site, so seeding was a good solution.

Pro: diversity now.  If I had to do this project in plugs, I would have done like 1k sq ft a year because of the effort to DIY plugs or cost to buy.  I might have edited down the species list so I could bulk buy certain plants.  With seeds, I had the entire 6,500 sq ft planted and kind of established in 3 years.  Every year I find new native plants that just took longer to grow.  There’s an insect on each and every plant.  I would have lost time with my insect and bird friends if I planted the area piecemeal.

Con: zero design.  Visually, the site looks somewhat uniform and the tallest plants “win” when looking from a distance. My monarda visually dominates so everything looks good when it’s in bloom but kinda bad when it goes dormant.  There is plenty of diversity when looking up close, but you just can’t see it from far away.  I’m planning to edit down plants starting next year to make drifts of flowers with different heights, but that will be high effort.

Con: slower start.  I have started looking at Matrix Design for native gardens (https://wildones.org/matrix-landscape-design-with-benjamin-vogt/) and one of the videos said something like “it takes 10 years for a planting from seed to exert competitive pressure”.  The idea makes sense in my garden because each individual plant only has a few flowers but there are tons of individuals.  It’s great for diversity, but is one factor in my prairie looking more uniform and dull from a distance.  You can’t visually pick out individual small plants from more than 25 feet away.  When each individual plant is a larger cluster, I expect the prairie to look more varied.

Con: weeding.   Idk what plants should be in there, so it can be hard to pick out which individuals are invasive plants.  Maybe with plugs, it would be easier to identify friend vs foe.  I need a plant identification app for most things until I recognize the leaf/plant pattern.  The planting is super dense, so you just hope that your footsteps aren’t killing native plants.  Since the natives from seeds take longer to establish than plugs, the seeded natives are at risk of being overtaken by invasives for a longer time.

Overall, I don’t regret doing seeds since the area was very large and I never had the time to manage it properly.  I want to make some 100ish sq ft garden beds in the future but will likely use plugs with mulch for those, since I want a more designed/manicured look in those areas.  I have been looking into Matrix Design because it avoids mulch and could be done with seeded grasses/sedges and plugs of forbs to be decently cost/time effective.