If the ground is nice soil (not too hard, rocky, sandy, or filled with builders rubbish) then its really personal preference. Raised beds are good if you have a bad back and people are less likely to walk through them leading to compacted dirt. But straight into the ground is also fine, you dont need to source dirt to fill it, and I find turning the soil over is easier when its straight in the ground.

I wouldn't do them just because of space. I'd argue they are less efficient and flexible for space. I do have raised beds and water drainage early in the season is a significant factor for me. A plastic tunnel house and improved drainage gets me significant season extension on the season with raised beds over in ground for many of the crops I grow.