My first bitcoin buy from Local Bitcoin and it was my favorite p2p site. But I don't understand why and what is the main reason to closed buy/sell service by local bitcoin?

I knew Localbitcoins but never transacted there simply because it's an old way of exchange, they've had their good moments when cryptocurrency was not as exposed as this and working in the old way is primarily the reason I believe they stopped operation, they couldn't meet up with the competition. This is the second time in less than a year and I believe they are going for good this time.
Come to think of it, they are doing KYC, this is despite that their transcription fees are so high. I don't think it would be a smart idea for anyone to deal with them when they can easily deal with regular exchanges like Binance with low fees.
In other words, cheapness and ease of doing business within exchanges might be the main cause of this, people are taking their businesses elsewhere.