Pros and cons?
I also hear you can assign multiple eSIMS to phones... which has got me interested.
My regular domestic cellular service uses the nano SIM slot.
For international travel, I purchase short term cellular data plans with my eSIM using Truphone (there are other companies like Ubigi). This is more convenient than hunting down and fumbling with a SIM card in a foreign land. I can typically activate the cellular data plan in about three minutes -- often while I wait at the baggage carrousel.
Multiple services can be assigned to the same eSIM. You just choose which service you want active with the eSIM. At least for travelers, this can be a boon.
If you only use one carrier and you don't travel internationally, I don't see how an eSIM would be of any benefit.