The human voice was designed to make a huge gamut of sounds: soft and loud, high and low pitches, many tonal qualities, many stop and start patterns, sustained tones or extremely changeable riffs, runs, slides, and other gymnastics. The physical skills that the singer must train, like those of the baseball player, gymnast, dancer, potter, blacksmith, or chef, benefit from intelligent exercise.
If you sing repertoire that is limited in some of these areas, you might think that exercising all the varied functions may not be necessary. However, the voice was designed to do all these things, and benefits from doing all these things. Your whole “vocal body” needs to get some exercise in order to sing your best over the long haul.
If you are not a singer, a few lessons with a function-oriented voice teacher can help a lot with vocal stamina, expressive capability, and confidence. If you are a singer, voice study is very important in order to improve your instrument, expand your repertoire, and to re-tool when your voice changes due to life events or age.
Do not fear a “weird exercise” if it is exercising your voice in one of the areas above. Just beware of a training program that ignores one of those areas completely. Your voice and body need interesting things to do to stay vital!