The matte and gloss decision changes when a planter is tall. On a low bowl the difference is a detail. On a column at eye level it is the whole character of the piece: Gloss Bright White picks up a highlight down one side and reads as an object, while Matte Bright White stays even from every angle and reads as part of the building. On a facade or a repeated run, matte is the usual specification for exactly that reason.
Height also decides how much of the planter a person actually sees. A tall white planter is viewed from the side at close range rather than looked down into, so the wall is what you are buying and the finish on that wall matters more than on any other shape. It is worth knowing that white shows what lands on it. Both finishes wipe clean with mild soap and water, and the manufacturer is explicit about what to avoid: no bleach, no power washing, no steel wool or abrasives.
A planter appears here when it is offered in a tall size and in one of our two whites. Several of these families also come in short sizes, so read the size table on the product page rather than assuming every option is tall.