If that’s all you need, and you don’t plan to raise money, apply for loans and don’t intend on bringing in partners, then you certainly don’t need a 25lb manuscript. In fact, Brian Chesky (found of Airbnb) is famous for his one-page business plan for global domination.
Yet, some may also think that pitch decks and clever presentations may he displaced them.
Every entrepreneur and startup company needs a plan.
If you are planning to go to a local bank for a business loan, or are approaching your sphere of influence for backing who you know is accustomed to seeing legit business plans, then you know you probably need to create something that they understand in a format they are comfortable with.
Business plans and pitch decks are two different things. Yet, one is for presenting and specifically for getting funding from angels and VCs.