I don't think there is much difference in what you are saying. Trading through API is quite easy when you have the right tools like a trading bot like
Gunbot. You could input there your API and start trading right away and automatically, 24/7.
As for the accumulation of Bitcoin, maybe you are talking about compounding your money and continuing to load Bitcoin until you have a lot of BTC? That's like what it sounds to me. Maybe you can clarify it a little bit more?
yap . thats it ! i just keep some of my bitcoins on exchange , with a trading api , no withrawal , and a few months later i have more 10% btc , or 20% btc , instead of just holding in my cold storage wallet