Dutch white clover grows up to about 5 or 6 inches and produces 3 or 4 roundish leaves. The true Dutch white clovers will exhibit a white ring going through all three/four leaves. Here's a picture...

Clover looks weedy when it does not entirely cover an area. If you have a grassy ground cover with patches of clover, it can look pretty unkempt. However, if the entire yard is clover, that can look very luxurious. Once it gets up to 5 inches tall it stops growing. If you mow it then it scalps off all the leaves except for any shorter growing plants. The white flowers attract bees, which makes this a poor choice for yards with children or pets.

Clover kills other plants by providing too much shade for them. Low growing plants will be wiped out. Fast growing grassy weeds might sneak in, but a shot of Grass-b-Gon should take care of that.

Plenty of weeds can compete with the likes of white clover. Then your issue will be how you selectively kill those weeds and not the clover. If this is a low maintenance area of your lawn that you don't want to fertilize or apply weed control, fine. Otherwise leave it out.

Excellent point by mishmosh. Grassy weeds might not be able to compete but other broadleaf plants can.