bandwidth
The SWR bandwidth of a folded dipole is less than a cylindrical dipole of the same spacing between wires. It is very difficult to make a dipole of 10% bandwidth of SWR under 3:1.
On the HF band frequency assignments for a station are in narrow ranges. They use dipoles in parallel, one resonant for each band.
The popularity of the folded dipole is that you can feed it with 300 ohm parallel wire line which has low loss. This is good for the VHF band.
Since transmitters and receivers of all types are designed for 50 or 75 ohm lines, it is best to use a feed line and antenna at those impedances.