I'm looking at getting a new phone next year, and one of the new features is the opportunity to have a digital eSim instead of a physical sim card (or have both).
The big pro for me would be the number of virtual sims that can be stored. That means it's easy to switch networks should you need a better signal. It also allows for two numbers on a single device.
Cons... I imagine it's harder to switch hardware as there's no SIM to swap.
I believe there are both pros and cons in relation to security but I'm not entirely sure what they are. It's also worth noting this is still new tech which may not be readily available across all providers.
eSims are a game changer. I remember switching phone services a few years ago, and having issues with a regular sim card. When you sign up, you would have the process of waiting for the sim card to deliver, which would already be a little bit of a delay. Then I had the issue of somehow damaging the sim card putting it into my iPhone incorrectly (that's what they said anyway), and suddenly I was without service until they could get another sim card shipped to me. I no longer had the previous service, as I had went through the process of moving my phone number over and all that jazz. Then they were telling me that they couldn't even expedite a replacement sim card, and I would be waiting 5-7 business days or some nonsense. 😛
I've been with the same service since then, but when I upgraded my phone, it was a nice surprise moving to an eSim. It's much simpler. You don't have to worry about accidentally jamming a sim card into your phone incorrectly, and you don't have to worry about losing it either. It's also awesome that you can be on multiple services with your phone. I took advantage of a free trial that T-Mobile had a while back, and that was where they just put another eSim on my phone, so I had two services running. It's a great way to compare/contrast one carrier over another. You can really tell the differences in speed and things like that.