Oh i think its always best when they allow for altcoin investments and not just the big 2-3. Even if they have to use a third party convertor that accepts altcoins and they get btc/eth, being able to invest third party coins that we have in a project is a great incentive for buyers.
We are coming to that stage where atcoin is going to be a big choice to many cryptocurrency adherent like my self. I believe there is great potentials in altcooin