I believe that this reply will main depend on the size of the company: larger companies or multinationals will have dedicated teams for sales, marketing, finance, so they will no require their team members to have additional skills in area not primarily related to m&a. A good level of finance is, anyway, fundamental for working in internal m&a or corporate development. A really good and capable employee, finally, who has knowledge of these additional areas, will definitely be an added value for their company and will be able to analyse the target from multiple perspective.
