Stack packs are popular on bareboat charters. It's a simple way to stow a sail and keep it covered without going to the bother of furling it on the boom if you don't have roller reefing (where the sail is wound around the boom), or roller furling in or behind the mast. It obviates the need for lazy jacks or Dutchman sail stacking gear. Deep water cruisers generally eshew stack packs because they add topside weight, and windage, and are thought to spoil the air flow when close hauled. We use lazy jacks and either do a quick furl or a 'harbor' furl (which is tidier) depending on how long it will before we set sail again. The foregoing presupposes that your boat is of nominal size and able-bodied crew are available. A decent stack pack is costly. Lazy jacks, grommets and sailcovers, not so much.