You are a newcomer or an established development team and you have the idea of developing your product. What's worth thinking about.
Let's say you have an idea for an app with a full set of features and options, however, it is not verified, and you can't guarantee if it will have success among the users. This is where the MVP comes in handy to test your idea.
Or you are thinking about attracting investment to your project. An investor needs to tell about your product, show the functionality, and here MVP comes to help.
Someone will object "why do we need an MVP if we have a prototype + presentation". A prototype is proof of the technical feasibility of an idea. It can be unfinished because it does not need to show the result in the real market and get feedback.
The MVP is an early version of the product that contains the minimum possible functionality, but at the same time, it is not crude or unfinished. It should answer the question of how viable and competitive the idea is. With MVP, you get users’ feedback and learn from the market.
If you have an MVP + prototype + presentation you can apply for participation in the grant. Be prepared to defend your product is a challenge, but it is worth it

Start up - is a good stuff. But only if you know what to do

Fair point. If you don't know what the startup is about, it's going to be difficult. That's why some steps need to be taken. Develop an idea, conduct a small survey with your audience to determine the viability of your idea. After that, you can look for developers to create your first MVP to see how it works and make adjustments. Startups always go by trial and error, the fewer the better. If you are interested in the MVP theme you can always find different startup reviews like here https://freysoft.com/blog/what-does-mvp-mean/, read entrepreneurs' communication, read the audience's opinion.