I used to think pricey interconnects were snake oil...

Refrain from what? I thought I was being amusing. So called "snake oil" does have some therapeutic properties however minimal, Perhaps we use that word recklessly and impertinently when we bandy it about in audio land.

My 2 cents worth.

1980's I read brochures from what I could get at stereo stores. Monster cable, interlink 250 $50.00 Straight wire. I settled on these 2 because of cost. Then circa 2018. I moved to Kimber Kable heroes and Cardas cables Iridium and crosslinks. ~ 200.00. The difference was immediately apparent. Clarity,imaging I still have the older cables and I often use them as a filler until new orders arrive. I'm a believer.

Hello saulh!  Take a magnet and check the plugs for ferrous metal. Plating won't help. If anything sticks, it's not what you want. Hoppy Listening!

They are.

I went through a variety of xlr interconnects from the likes of Audioquest, Moon Audio and others. They were okay, but it wasn't until I got some AntiCables gold/ silver alloy that I found what really worked for me and my system and at a price I could afford.