You need to outrank serious competitors
Squarespace's SEO is better than Wix's but still capped. Custom-coded sites can implement every modern technical SEO pattern (canonical control, hreflang where needed, structured data graphs, llms.txt, fine-grained Open Graph). A Lakewood Ranch dentist competing against established practices needs that depth.
AI search citation is the goal
Squarespace ships partial schema and no llms.txt. AI engines that look at your site (ChatGPT Search, Perplexity, Claude, Gemini) get fewer signals to work with. Custom-coded sites can ship the full GEO stack — linked-graph JSON-LD, llms.txt, llms-full.txt, IndexNow auto-pinging, AI crawler directives in robots.txt.
You're paying for a designer anyway
Hiring a Squarespace expert ($1,500–$5,000) to customize your Squarespace site lands at roughly the same upfront cost as hiring a developer for a custom site. The custom site comes with no monthly Squarespace fee, faster performance, and no platform lock-in — strictly better value at similar cost.
You want to integrate things Squarespace can't
Custom CRM, custom booking, custom membership areas, sophisticated forms with conditional logic — Squarespace's third-party integrations are limited and often clunky. Custom sites integrate natively with whatever your business actually uses.