Well if we are talking about the end user, it is all about some form of lending to be honest, but it will become more useful platform with time and it will help some projects to become reality that won't be focused on lending and various forms of lending.
DeFi is not only lending but it also focuses on borrowing, algo trading and creating synthetic assets. Defi in my opinion is currently very hyped and after few years this bubble will burst. Saturation point will come one day. If you are an investor and want to earn good profit then you should invest in DeFi.
The top highest ROI generating DeFi tokens are still below $5. You can still ride on the the top 5 to make some good profit before this year ends.