That's a perfectly good way to play, and it definitely was how I played for a long time.
I strongly recommend that, even if you aren't trying to earn platinum yet, you should join the in-game Syndicates sooner rather than later. They're key to earning later in the game, but it requires quite a lot of effort to get to that point and it's better to start early while you don't *need* them so that they're ready to go when you do.