There's a seam in most WooCommerce builds. You see it as a button padding mismatch. A different border radius on the checkout form. A font that's almost the same. The moment a customer notices the shop doesn't quite look like the rest of the site, a question forms: is this the same company?
For Haila Health - a Canadian CBD wellness brand - that question is the one you can't afford to raise at checkout.
I built the theme from scratch with WooCommerce as a core dependency, not an addon. The standard WooCommerce content wrappers were unhooked on day one and replaced with the theme's Bootstrap layout wrappers. Shop, cart, checkout, account - every WooCommerce page renders inside the same grid and container structure as the rest of the site. The seam doesn't exist because I didn't build one in.
The WooCommerce form field normalisation is the most labour-intensive integration task in any Bootstrap/WooCommerce build. WooCommerce generates form markup with its own CSS classes. Those classes don't map to Bootstrap's form-control and form-group structure. The woocommerce_form_field_args filter rewrites every field type - select, country, state, text, email, tel, number, textarea, checkbox, radio - to use Bootstrap classes. Every form on the site: same markup pattern, same CSS rules.
Localisation decisions matter long-term. Cart/coupon terminology was replaced with basket/voucher using gettext filters - not template overrides. Template overrides require manual updates with every WooCommerce release. Gettext filters survive updates automatically. It's a smaller surface area to maintain for the same result.
The AJAX cart fragment keeps the basket count accurate in the navigation without a page reload. Without it, customers who add a product and look at the nav icon see a stale count. Small friction at a moment when trust matters. The implementation uses WooCommerce's add_to_cart_fragments filter to push updated basket markup to the page on every cart update.
I've done integrations at scale - WP Engine's Amazon Personalize recommendation engine, enterprise data systems for large Canadian organisations. The engineering discipline is the same regardless of project size: don't introduce fragility when you don't have to. Haila Health got the same architectural care.