To sail around the world the vessel needs to be equipped for offshore cruising and have a heavy load capacity.
The bigger Modern blue water cats are built with this in mind – supplies, crew, technology and gear.
A bigger boat has many advantages such as speed (not only to travel longer distance in shorter time but also to outrun potential bad weather) and comfort space, space for crew and friends, storage space for supplies and fun equipment, etc.
It is important to balance price against comforts, maintenance and repair costs as well as any potential income from your vessel (chartering, Air BNB, hosting courses on-board, etc) – generally here the bigger your vessel the higher the potential for greater income.
The larger your vessel the higher your expenses are in all ways – from Insurance to berthing, maintenance, haul out fees and equipment.