What is a CDN and do you need one?
A CDN (content delivery network) places copies of your site on servers worldwide, so visitors load everything from a server nearby. It makes your site faster and absorbs traffic spikes. For a strictly local audience it is optional; with international visitors it is near-essential.
Without a CDN, every visitor loads your site from the one server where it is hosted. For a visitor on another continent, that means a noticeably slower visit. A CDN fixes that by copying static assets (images, scripts, stylesheets) to dozens of locations worldwide and serving each visitor from the nearest point.
A CDN also offloads your server: most requests never reach your hosting anymore. That helps during traffic spikes and forms a first shield against denial-of-service attacks. Cloudflare is the best-known name, and its free tier is enough for most sites.
Increasingly it simply comes included: Kinsta ships Cloudflare integration as standard, WP Engine bundles a CDN with every plan, and SiteGround has its own built in. If your audience is in one country, a fast server nearby is half the work and the CDN is the finishing touch.