So for my post, can I just link to Jeffe's post and nod vigorously? No? Rats. Okay. Let's come at this another way, then.
Sometimes, mes amis, the world of publishing leaves you very few options. When what you write isn't necessarily the flavor du jour, most trad publishing houses won't look at you cross eyed. If they do, but your sales don't hit a particular benchmark, you may rapidly find yourself unpublished by traditional houses. If that happens, and if you have the self-confidence and spite to pick up your stories, you can go home and learn to become your own publisher.
Or say you've been writing one genre and you want to dip your toes into another - one you aren't necessarily certain you want to immerse yourself into. You write that book and rather than subbing it to agents and editors, you put it up yourself as an experiment. To test the genre waters, so to speak.
Or, maybe, after an eternity of waiting, you recover the rights to a group of stories that were orphaned when your cherished editor left the business (get used to that one, cupcake, it happens on a daily) you finally have the opportunity to finish out the series and relaunch the whole thing at what you consider a much friendlier price point - or with the cover of your dreams. Whatever your entre into DIYing it is.
Just know this. Everything about self-publishing is learnable. Scads of people have been through this wilderness and will gladly point the way. Some people will charge admittance. Many more won't. Author loops are crazy generous with how-to information, software suggestions, cover designer, editor, and copy editor referrals, too. Most of them will discuss the nuanced differences between launching wide versus targeted, too. Here. Let me pass you an aspirin. Author loops are a fire hose. You might need the pain killer.
All of this said, there's no right or wrong answer to the question of going indie or trad or both. There's only what's right for you and your work. If you're a security seeker, go trad. If you're a risk taker and a control freak, go indie. If you see the merits of both, then do all the things. There's really no math to do that will make clear which path is 'best'. It's all judgement call and what sounds like the most fun. Sure. You need a career strategy at some point. Tons of people will coach you through that, too, but as far as I can tell, you end up with a mirror of THEIR strategy rather than one of your own. So you may as well be guided by your own sense of what sounds easy versus hard. If having to format your own book sounds like the third circle of hell because you're a technophobe, you can hire someone to do that work, or you can choose to stick with the trad houses. They'll handle all that fiddly stuff, at the price, however, of having complete control over how your book is presented to the world.
So. Yeah. What Jeffe said. It's all about tradeoffs. You get to choose which ones you'll accept.