Why are simplex channels designated in the VHF/UHF band plans?

Simplex channels in the VHF/UHF band plans are designated primarily to allow stations within range of each other to communicate directly without relying on a repeater. This promotes efficient use of the available spectrum, as simplex operation requires only one frequency for both transmitting and receiving. In scenarios where operators are close enough to connect directly, it alleviates unnecessary traffic on repeater systems, thus freeing those channels for other users who may be further apart and require the extended range a repeater provides.

While there may be other valid scenarios for using simplex frequencies, such as contest operations or working long-distance contacts (DX), these do not capture the primary purpose of simplex designations. Additionally, the option regarding stations with simple transmitters accessing the repeater does not pertain directly to the definition of simplex channels, as simplex implies no repeaters are involved at all. Therefore, the focus on direct communication between stations, as facilitated by the assignment of simplex channels, highlights their fundamental role in the VHF/UHF band plans.