tv plus content in Israel

Is there any geographical restriction?

The Apple ID should have set a proper region (by billing address), matching the iTunes & App Store region. That region should also match your geo-location (IP address region).

There is no further restriction for your location. Apple TV+ should be regularly available in Israel. Availability of Apple Media Services - Apple Support

Why would I be restricted to watch the content I subscribed to?

In general, the content providers have thought that regional licensing works best for them. There are not many details on this publicly available yet for Apple TV+ specifically.

What is the solution for traveling people?

Contact Apple Support for further inquiries.