Convenience
An eSIM is delivered by QR code in minutes and installs without opening your SIM tray. Physical SIMs require finding a store, showing ID in many countries, and swapping cards you can easily lose.
Dual-SIM advantage
With an eSIM you keep your home number active for calls and banking SMS while all data flows through the travel eSIM. That is impossible with a single physical SIM slot.
Cost
Travel eSIMs are typically cheaper than airport SIM kiosks and dramatically cheaper than roaming. There is no shipping, packaging or store markup.
Security
An eSIM cannot be removed from a stolen phone the way a physical SIM can, making it harder for thieves to hijack your number.