Trading involves a lot of activity and constant tracking of price movements. A trader normally has to be fully involved with the happenings of a stock market on a daily basis.
For majority of retail investors though, investing is about using savings to get a reasonable rate of return for investment in stock markets. Also, a retail investor might have a day job leaving limited time for him to dedicate to the markets on a daily basis.
Also, long-term investing is less likely to be volatile than trading and might suit the average retail investor.
Considering all these factors, it makes sense for a retail investor to follow the investing approach.
Overall, an individual should follow that he/she is comfortable with and also one that helps them get the best results from the stock market.