It is not an empiric choice. They fill a distance gap and based on how they can control the flight, they pick hybrid or fairway. If they would use an iron from the deep rough, they won't need a "rescue club". Really an individual preference. My reason for carrying a 7W is for an entirely different reason - slower swing players may use woods better than hybrids..

I would not say "better" but would say different. Nice that we have options based on personal preference and courses we play. PGA set ups are seeing more shaving around crowned greens and unless a lot of rain, are making greens firmer and faster. The 7 wood has a bit higher ball flight than the same loft in a hybrid but the hybrid has more versatility from different lies with its smaller head shape. Go with what works best for you, even consider having both and alternating based on courses played or weather conditions.