Skiplagged a good idea?

I’m planning to fly to Seoul in a few months and a direct flight there is $700+, but if I route to Ho Chi Minh City on the same day instead, it’s $300 with a layover in Seoul. That’s a huge difference and would get me to Seoul either way?? I was thinking of using Skiplagged, or just booking the HCMC flight on Google and skipping the last leg, but I know this is “hidden city ticketing” and can get me banned from the airline. Honestly it’s Korean Air and I don’t plan on visiting Korea again after this so idrc if I get banned.

BUT what trouble might I get into otherwise? Will Korea not let me into the country for some reason? I don’t plan to check luggage, but can I at least bring a carry-on? I actually do plan on going from Korea to HCMC after, but not until like a week after lol. Has anyone done international hidden city ticketing like this before? How was your experience?