What exactly is microStrategys strategy?

I do not understand how this company operates its bitcoin business model. But maybe I have a few misconceptions...

MSTR now holds around 5% of BTCs circulating supply. Periodically buying more. The CEO says they will not sell. If they did, that would send a massive signal to the market affecting sentiment and price. If they sold large portions of BTC that would affect price more. How can something that can never be sold unnoticed and without negative impact on its value even have value? Every public transaction of course affects market price, but here movement is closely monitored. Also, does this not slow adoption of bitcoin when more and more assets are locked? Or does this not matter because it is nearly infinitely dividable?

What value does this company add for someone believing in bitcoin that can not be done by simply aquiring bitcoin themselves without the middle man and have self custody. Or is this a leveraged gamble? Or is it a gateway for people who cannot legally obtain bitcoin but may obtain the stock?

Could someone explain? Really struggling to understand this. To anyone invested. Can you explain why?

Thank you