What is the advantage to the cell of having different organelles that carry out specialized functions?
Each cell can be more efficient.
Without having these little organs within the cell, it could not carry out essential functions. Also, each cell carries such specific information to the make up of the organism and specific features of the organism. DNA replication is carried out by a specialized function of the nucleus. Such a delicate process would certainly not be performed as perfectly if it were not performed by a specialized organelle. Just as the vacuoles hold food and waste.....if not the waste would just be floating about randomly in the cell ?? That could probably interfere with other functions. Some vacuoles help keep the pressure balanced in the cell...if not the cell would collapse. Check out the links below.
The advantage to the cell is that it is more efficient to have membrane-bound organelles specializing in certain functions, than in spreading the cell's necessary functions randomly throughout the cell. The organelles can also be in logical proximity to others that have related functions. For example, organelles producing proteins within the cell can be near other organelles involved in transporting the proteins out of the cell.
I think of it in terms of a school. What if everyone taught everything and did all of the administrative task? We would all be generalists and would not give our students the best education possible. Organelles are specialists. If there was just one major organelle the cell would not function efficiently, and would eventually die off.