Travel

"most valuable piece of advice I can give you..."

more valuable than your previous gems revealing your near-total ignorance about banking, travel, and credit cards?

lay it on me.

"It's utterly unlikely that you'll ever find any credit card that has so good conditions that it'd make up for that loss."

this is objectively untrue with even basic introductory benefits for most credit cards negating the credit card annual fees, most cards specifically offer no-fee foreign transactions...jeez dude, just say you don't know or ask a few questions; you don't have to keep pretending you know anything with vague assumptions and half-baked notions.

All you're doing here is further exposing your ignorance.

" you need to tell what currency you have income in"

nope, makes absolutely no difference within the context of personal experience with credit card benefits, which is the topic here.