If you have developed partnerships with other companies (or you'll need to develop some specific partnerships), and those partnerships are critical to your success, or provide some specific capability that is an advantage, you'll want to discuss that in the plan. If there are dependencies you have on partnerships -- relationships that will cause difficulties if for whatever reason the relationship doesn't work out -- that's worth discussing also.
Beyond the specific benefits related to partnerships there are two general potential benefits:
- Strategic partners can serve as excellent references for potential investors.
- Strategic partners can be a source of funding. Many large companies have venture funds. Others make investments even though they haven't structured a venture fund.
And there are non-equity possibilities for obtaining funding from strategic partners. If you need products or services from the partner, it's sometimes possible to negotiate favorable discounts and/or payment terms presuming that the partner eventually receives some other benefit from the partnership. Sometimes strategic partners are also customers, in which case selling them product (perhaps even selling them product before the product exists) is another funding possibility.