If you want some profession-locked transmogs it’s certainly an idea, but as things stand right now, there’s no progression benefit to it. Most gear is obtained through M+ and raiding, so in terms of PvE alone there’s not much reason to grind tailoring.
If you’re in it to make transmogs (and I think there’s a mount or two as well) however, go ahead!
In Retail, you level FAR too fast to make use of your profession. By the time you work your Tailoring up to making useful gear for yourself, you have far outlevelled it. And it’s even messier now, with each expansion having its own section.
It can work in Classic/TBC, if you remember to keep your crafting skill up, but not in Retail.
There was a window to make some gold by craftng gear at the start, and at 9.1, but we won’t see another such window until 9.2, and it may be brief and weak.
Eventually, you absolutely can use Tailoring to make yourself pieces for transmog. (You can probably buy them with less hassle tho) It’s not a great business, but if you diligently list a hundred or so pieces a day, like shirts, and you don’t have determined competition, you might make something in gold. I wouldn’t rely on it, though.
I seem to recall some few, old tailor items being usable only if your tailoring was at a certain skill. In hindsight it’s possible that isn’t the case anymore.
If a crafted item is Bind on Pickup, it will be immediately Soulbound to its crafter when made, and can’t be traded.
There aren’t many of these, but those appearances can be acquired only by someone who has the profession. However, once learned, other characters of yours could also use the appearance.
I’d namely try and sell high-level crafts (that are locked behind the 75 skill cap, aka epics) that look very pretty, especially if the pattern is hard to get as well.
Say, Soulcloth Vest is sure to fetch a buyer for a few hundred bucks, but Cindercloth Vest and Pants (what I have on) will usually sell to your transmog collector as well.