It appears to be very popular in Latin America. So the pronunciation of iZettle by a Spanish speaker most likely sounds like "e-settle".

Which makes a bit more sense and Def sounds better.

It's a Dutch company, so not sure how it sounds when pronounced in the Netherlands

Much easier to search for

Maybe for English-speaking countries. But iZettle is market leader in Europe and LatAm, so the counterargument could be that iZettle is more visually memorable and easier to pronounce than e.g. Square if you are not a fluent English speaker.