Yes, I do. Beacuse it is simple and clear. I use it to understand the price movements and currency pair trends. It's actually best for beginners.
Today i used line charts and was up 10% in 21 minutes. I've been trading since 1987 when i had to phone my broker at a pay phone to place a trade, long before cell phones and online trading. Until this day i still go back and forth between bar charts and line charts. Once again I'm trying to simplify my stratgey. I consider my skills less than average and i try to dumb down the process to help me. Line charts provide a cleaner, more straightforward view of price trends. When using line charts, I feel less cluttered or less distracted by the additional information in candlestick charts, and find that line charts allow me to more clearly see the price action I care about.
I created a sparkline sheet yesterday just for amusement to see if it had merit for me. The Tether, Doge & Link wont work as for some reason are not recognized. Just some more ordinary currencies.
I built custom charting software and it can do 1sec charts. I have so many screens, that I can have candle, line, tick, etc all at once. Line charts are useful. My best momentum analysis algo recolors line charts based on a complex function of price changes. For most purposes, I think line charts are superior, but a good candle chart can allow very quick assessments.