Short answer
eSIM and Second Phone are different products.
eSIM
Gives mobile data for travel.
Does not include a regular phone number.
Does not provide regular calls or SMS.
Best for internet access while traveling.
Second Phone
Provides a phone number for calls/texts depending on the plan and supported regions.
Is a separate app/product.
Best if you need a phone number for calls, texts, or registrations.
If your issue is about mobile internet while traveling, choose eSIM support.
If your issue is about a phone number, calls, or texts, choose Second Phone support.