If you hope that your potential customers will pay significant money to obtain your products or services, you need to present them with a proper business case—once they’ve been identified as qualified leads. Don’t confuse a proper business case with a value proposition.
Don’t confuse a value proposition with a mission statement. You need to be prepared to talk about money. Having a great product or really smart people isn’t enough by itself. You need to demonstrate your value effectively with quality sales materials.
Sales presentations are critical to success of your sales people when they meet with prospects. Usually these contain a mish-mash of marketing slides designed by your marketing people/department, technical slides designed by technical staff, and last-minute slides designed by your salespeople. This means that your most important sales tool is at best inconsistent, and possibly incoherent. You need to at least have it vetted by a third party.