Tags are searchable keywords associated with your product.
For example, if you have a t-shirt store, you may choose to tag your shirts by color. So that a customer can easily search/browse yellow shirts only.
On Shopify, tags can help customers find your product through your storefront search, and you can also use them to create automatically create collections based on how you tag your items.
Shopify wins because Lemonstand doesn’t have a dedicated field for tags. However, it’s a very tiny win that’s probably closer to a tie because Lemonstand and Shopify categorize products in different ways.