Valid breadcrumb schema can make Google display the page's category path (Home > Category > Product) instead of the raw URL in search results — a small but real trust and clarity signal for someone deciding whether to click.
Breadcrumbs are often implemented visually on the page without the matching BreadcrumbList schema markup behind them — the navigation works for humans, but there's nothing for search engines to read as structured data.
Run a product or collection page through Google's Rich Results Test and check specifically for BreadcrumbList detection — a visually correct breadcrumb trail on the page doesn't guarantee the schema is present or valid.