If you’re concerned about performance and still want to be able to use the WooCommerce Shipping & Tax plugin, consider keeping Jetpack installed but disabling any modules which aren’t needed or which aren’t directly related to actually speeding up a site (such as the CDNs).
I looked at the full list just now and I think these modules would be good to keep at a minimum:
* JSON API
* Notifications
* Site Stats
* WooCommerce Analytics
You _might_ be able to turn off the stats and analytics too, but those are nice things to have! You might want the Protect option on to help block malicious login attempts, that’s a good one. Also consider keeping both CDNs—those should actually work to speed up a site but many people mistakenly think they do the opposite because of how the images and assets are cached on demand, in other words those things are cached as they are accessed after the setting is toggle on… so it’s likely some pages would be slower *the first time* the first person (usually the site owner!) hits the page after turning on the CDN features because that will trigger caching and only then will subsequent views after that load more quickly, especially globally, because those CDNs take advantage of larger scale resources that most hosts don’t provide for free. Anyway, it’s a complex topic! and I think a lot of the speed issues are misunderstood, but you can turn off most of the modules if you don’t want them or don’t want to try them out.
If you are really concerned about performance, the best possible things I think you can do are to get a good web hosting provider that is rated well for speed with or without the Jetpack plugin on a WordPress site and make sure any other plugins you install are from trusted sources.
Thanks for trying out the plugin and for posting to ask an honest question about it!