It's very much possible you can do it, there are people who have lunched certain products to use and promote certain coin but they don't make that coin the sole method of payment because if such is done , not all customers will be comfortable using such payment method, they may result to other options if they happen to find it difficult using that payment method or if they find it not comfortable enough, so it will be better you make option for other payment method but paying with the coin you hope to promote comes with certain discount rates, that way it will attract the attention of others to want to try out the new coin so they could get a discounted rate but solely making that coin as the only means of payment may not be effective enough as it will not be friendly to those who aren't crypto enthusiast thereby reducing the customer base versatility.