Both of your friends would love digital products.The one with a product says, I want a service where I don't need to worry about inventory and importing. Plus it costs so much money to purchase inventory.
The one with a service says, I want to sell a product so I don't need to deal with my customers and phone calls. I want to sell a product and let Amazon handle all the customer service and shipping.
No inventory. No importing. No investments to purchase inventory and the servers are quite cheap.
No phone calls. Minimal customer service. No shipping.
A big investment upfront to create the product and some relatively low recurring improvement costs.
From my short experience with both, I would say products are more fun. That's probably partly because I'm currently in services for more than a year.
With services, you're actually managing the service more than doing sales/marketing. You're getting paid for your time which is hard to resist in a small company plus hiring people is a pain, especially in high-skilled fields like software engineering. We get 20+ relevant CVs per position, talk with every one of them, and do 10-15 interviews to hire one developer. There are two interviewers, so it's roughly 45 hours to hire someone great.
Services do scale well, slow, and steady. I would also say they're more stable at any scale.
On the other hand, the web product we had crazy swings with almost 0 profits during the COVID lockdowns and more than service business can make at the current scale in a year on best months.
With product business, you have more free time for high-level thinking and taking actions based on that. With services you're stuck in the business 80% of the time, have 20% time for sales and thinking. Taking actions on evenings and weekends.