Unless you are a HF trader, you probably only need the stock price within a few minutes unless you are about to place a trade. (And typically all these terminal stock tickers are doing is scraping these sites anyway so the data is about the same.) Therefore, during the day I can watch stocks in the comfort of my terminal using mop [1] (or this if this has more features and is as easy to use), and if anything strikes my eye I can then go to my stock trading terminal and watch things more precisely.
I also do have a custom search engine that can open any stock ticker to finviz.com but I'd rather not have to have yet another account on some random website that either has distracting ads and/or pushes me to pay for more features.
There is a very large UX vs features trade off when it comes to anything stock related so it makes sense to use multiple tools.
It's a pretty handy app, that seems to be constantly up to date, but it's garbage on Mac, so I setup a PC laptop next to my main setup so I can have it running. Still a bit finicky on PC, but way better.
But if all you want is to watch trends, not do HFT, being even 5 minutes late is fine. Even just looking at how a day went after hours is fine.
If you are interested enough to regularly check the price of certain stocks and indices you know that the most important thing is that the shown price is CORRECT. And you know that the most trustworthy way to get a correct price is to go directly to the largest brokers and the largest and most trusted portals like Investing.com and Marketwatch.
On the other hand if you don't care that much. Why the hell would you like to have a special application for checking when you could as well go to any of the above?