What is SMC Forex trading?

they were all identified years ago. Some examples are common gaps, exhaustion gaps, breakaway gaps, and runaway gaps.
You will discover that other SMC concepts also are familiar to you once you figure out what the fancy terminology is referencing.

When analyzing the markets, SMC focuses a lot on "break of structure" in the market, or "BOS."

Here is a chart illustrating breaks of structure. Every time price surpasses the previous high, there is break of structure. We then see a change of character (ChoCH) as price drops down past previously established lows.

be easier to talk about support and resistance.

Pros and cons of SMC
Pros of SMC:

Smart money concepts trading does seem to work for some traders. If it works for you, there is no reason not to use it. Being able to consistently grasp what price is doing and profit from its behavior is more important than knowing why price is moving the way it is.
Price action has a decades-long history of producing results for many people across not just currencies, but other assets as well. Since SMC is repackaged price action, it does have a solid core.
Some people find price action easier to understand when it is presented as SMC.
While the theory that large institutions are targeting retail traders is dubious, it does seem plausible to suggest that larger institutions may sometimes go after smaller ones, generating some of what we are seeing. Liquidity grabs do exist, even if SMC is presenting them in a questionable framework. So, some of the theory elements of SMC may be viable, just not as SMC describes them.
Cons of SMC:

Some of the theory elements of SMC do not appear to make a lot of sense when you think logically about how irrelevant retail traders are to the big players. Believing wholeheartedly in everything SMC presents could result in misunderstanding market fundamentals.
One can neither prove nor disprove the theories behind SMC. They are purely speculative, and only an insider would be able to produce concrete evidence in either direction. That means that no one can verify that SMC's model of reality is correct, but no one can 100% refute it either. All anyone can do is argue based on what they believe about what institutions do.
Switching up all the terminology the way SMC does can make for an unnecessarily convoluted learning process for price action, especially if you already are familiar with the standard language of price action. It may also make it harder for you to share what you learn with others who speak the regular price action language.
A lot of people are turned off by the elitist mystique surrounding SMC, and feel it is deceptive to sell old concepts as if they are new. Also, we are using the word "sell" here very literally. While there are a lot of free SMC resources, you will run into plenty of pay gates while trying to learn SMC.
Should you trade using SMC?
Smart Money Concepts trading would probably not be as popular as it is right now if some traders did not find it intuitive.

If you do like how SMC expresses its terminology and techniques, then by all means, go ahead and give it a try.

Just be aware that the strategy is a repackaged form of good old-fashioned price action trading, and that you are doing the same thing as many other retail traders.

But there is nothing wrong with that, because good old-fashioned price action trading is a tried and true method that has been profitable for many traders for decades.

If the strange terminology of SMC confuses you or you are looking for more free resources (there are paywalls for many SMC programs), just study price action. You will be learning the same thing anyway.