The two type of stickers look and feel different to the touch, with the key difference between matt and glossy paper being the “shininess” of the paper. If you ask us, the key influencing factor should be the kind of content that you would print in your sticker.
Glossy paper is shinier, looks like having high contrast and makes the color “pop” on the stickers. The extra shine works well if you are planning to load your sticker with a lot of colors and big graphics.
Matt paper has a more muted feel to it. If you plan to use light or pastel color scheme in your stickers or aim to have a lot of text on it, then you may choose to go with matt finish.
Having said that, it is all about the usage of your stickers, if you want your stickers to have more shine, then go with glossy finish, else matt finish works just fine!
Still not sure, order free sticker samples and you to see the difference between glossy and matt finish.