According to Meta, contacts are contacts, be it phone, email, FB, Instagram, etc. FaceBook already has all your contact info, including all your email and phone contacts - you agreed to those terms when you signed up. If you use Messenger, then you had to grant Messenger access to all your contacts as well, which also include your phone contacts. Granting the permission to WhatsApp is at worst redundant, Meta already has all your contact information.
Only people using WhatsApp can be called or texted, your business contacts and family members who are not on WhatsApp won't see or get anything. You would have to actively choose Settings, then Invite A Friend for someone not on WhatsApp for them to receive a personal invite from you. There is no automatic way to contact someone who does not have WhatsApp from your WhatsApp, you have to actively take steps to do it.
Meta, through Facebook, Instagram, Messenger, etc. already has everything on your phone including access to your camera, microphone, pictures, texts and contacts. WhatsApp is probably Meta's least invasive app. Facebook, Messenger and Instagram are much worse when it comes to data collection.
Should you still not want to grant access permission, you would have to follow the detailed instructions in the link I posted. There are some steps and restrictions that you need to be aware of if you do not want to grant access. Please read it in full.
If you grant access, virtually everyone and every business in Jamaica are available on WhatsApp. And you can make free encrypted calls and texts worldwide. Your phone's standard calls and texts, FB posts and chats, etc. are not encrypted and anyone who wants to listen or read can make that possible. There are software kits available on the "dark web" that are cheap and easy to use for just that purpose.
Granting permission to WhatsApp is probably the least harmful thing you will do that day on your phone.