It's so tempting to do a little bit of everything. All the tools are there, a click away. You can be the designer, the copywriter, the head of customer service. Hey, you can even do the manufacturing or easily outsource it to a commodity producer. One benefit of diversification is that you can average out your risk.
Or you can be a wallah. Someone who does only that one thing.
An old colleague of mine calls himself a chai wallah. Perhaps he loves spiced tea, but I'd prefer to believe it's a reminder that his success lives and dies on the performance of just one task.
When you go all in, it focuses your attention and effort, doesn't it?