Bigger area=harder control
Also it’s about the volume and surface area ratio. For optimum transport.

yeah pretty much, and also smaller the easier for nutrients to defuse within the cell.

look up "black perl" not the movie the organism, its pretty cool, and its only got 1 cell

Cells are also small because many transports in the cytoplasm are achieved by diffusion. However, for a distance double the molecules need more than double the time. If cells were bigger, processes would be very very slow.

I will give you some examples. Suppose that the shape of the cell is "sphere". then the volume of the sphere is (4/3)*pi*r^3, and the surface area of the sphere is 4*pi*r^2. the ratio of the volume to the area is (1/3)r. So as the value of r is increasing, the ratio is also increasing. Then the exchanging of materials through cell membrane is difficult.

If you’re panting a huge picture the smaller your brush is the more detail you will have

If you had a 1mm diameter cell, for human to function the human would be very big. And I think if cells were big the cell walls in comparison would be very thin since a cell wall is 2 cholesterols thick if I’m not mistaken. just like an egg. an egg is a huge cell if you remove the shell the membrane is very easily puncture able. Reason 3 maybe you’re too big. 😆