What is the formal word to say something is 'nice-to-have'? [duplicate]

I am writing a business plan for management, in which I wish to differentiate the options between that something is a must (mandatory) and other thing 'nice-to-have'.

The concatenated word 'nice-to-have' sounds less formal for business proposals, but I am not able to find a proper 'big' word. 'Optional' or 'alternative' might work, but it lacks the meaning that the option is perceived to 'be nice'...

Well, what I am asking is to seek a formal expression, and it doesn't have to be a noun. The context of the business proposal is like below:

After investigation, we believe that (1) The acquisition of XXX is mandatory as it's concerned with XXXX; (2) Taking ownership of XXX is always a nice-to-have, but considering current human resource, we may not take immediate action.

I usually see “desirable” for this usage. “Optional” is also used, but often in RFPs I see both headings, where those features listed under “Desirable” weigh more heavily than those listed as merely “Optional”.

As someone who has read and created business plans and requirement documentation in both my academic and professional career, I'd recommend sticking with "nice-to-have". This is common language in a Request For Proposal (RFP) or business plan, at least for IT Projects.

Alternatively if you are set on avoiding "nice-to-have", I'd recommend one of the following:

• High Priority and Low Priority
• Requirements and Requests

Or another less formal option that is used often in RFP's:

• "Needs" and "Wants"