Here are some points to consider whether to keep your original SIM and phone number as suggested by eSIM ONE:

If you keep your original SIM for calls: 

ROAMING FEES MAY APPLY: Your mobile service provider may charge for active call minutes and messages sent and received.

REMEMBER, COSTS COULD BE MUCH HIGHER: You can avoid mobile data roaming charges by using eSIM for data, but your original SIM’s provider may still charge for international calls and texts. 

If you choose to use an eSIM ONE as a replacement for your regular SIM:

NO INTERNATIONAL CALL/TEXT CHARGES: You won't have to worry about your mobile service provider charging for active call minutes and SMS messages sent and received.

How to install eSIM: https://esimone.com/check-device

Check Compatibility: https://esimone.com/check-device

eSIM ONE - One touch to the world