Last summer we didn't bother with a European SIM card. Had wifi and used iMessage, FB messenger and FaceTime for a couple of 'emergencies'. Now also using What's App.
After re-reading this, another eSim thread and other light research, I'm deciding the eSIM thing providing a second number on my iPhone may be above my 'tech'-scale. I don't want to mess anything up on my phone. I don't need to physically chat with family and friends back home by phone, only be reachable in case of emergency. I'm taking a vacation from them too and will connect to wifi daily in case something important comes up.
For an upcoming cruise that's mainly in Spain (18 travel days), I'm leaning towards taking my older iPhone and buying a SIM card with data that works for European countries so it works if/when I need it for any reason. Maybe to call a taxi. OTOH, I may buy it and never use it! Therefore, I may be better off just activating Bell's Roam-Like-Home for a 'day' if needed, for example, if flights need rebooking.
A friend bought a Vodafone S Prepaid SIM card from Amazon and activated it online before leaving for Spain for a land trip for three months. Worked great, can be topped up if needed.