Mining has to buy software requires a lot of money and paying for electricity also costs money and it takes time to get bitcoin the process is long so I use my money to buy bitcoins and I save I believe the bitcoins I save will be a valuable asset in the future.
The difference is that when you buy those equipment and you get into mining, and if you really have a proper operations and not just barely doing something, then there is a good chance you could double your investment.
So, if you buy 100k worth of bitcoin versus having 100k worth of equipment, in the end you could mine 200k worth of bitcoin with it, if the price of bitcoin goes up, it will be even easier. That is why some people prefer mining over buying, especially if they are living in a nation with cheap electricity rates. However, there are many of us who do not see the technological risks as a worth it investment, I can't be bothered with it if something breaks.