What makes an ecommerce idea worth pursuing in the GCC?

A product people rebuy, delivered faster than an international competitor can, priced in dirhams, and explained in the language the buyer thinks in. Any two of those is a business; all four is a defensible one.

Why the answer is what it is

The region rewards logistics more than it rewards catalogue. A store here can beat a global marketplace on delivery time and on service in Arabic, and cannot beat it on price or breadth.

What this looks like in practice

Test whether people will pay before building anything. A hundred people saying they like it is worth less than one paying.

An idea is worth almost nothing on its own. What is scarce is somebody who will keep going after the first version does not work, which is every first version.

The best ideas usually come from a job somebody already had. You notice a problem because you lived inside it, not because you brainstormed.

Where a mobile app comes into it

If the idea is a shop, the sequence matters: sell first, prove people come back, then build the app. An app before the customers is a cost with nothing to do.