How do companies “raise money” to buy BTC? What’s the pitch to investors? Why don’t the investors just buy BTC themselves?

Help me understand how a company like MicroStrategy is “raising money” to buy Bitcoin. If I were to give them $100 Million am I not just getting, in return, $100 Million worth of Bitcoin plus any gains? How does Micro Strategy make money? If I have $100 Million and want to invest it in Bitcoin, why not just buy it myself? What’s the benefit of giving it to Micro Strategy just so they can buy Bitcoin? It does not make sense to me—what is the value add here that MicroStrategy is providing to investors?