Actually, whether the timeframe of the indicator is 15 minutes, 30 minutes, 1 hour or 4 hours and 1 day depends on whether you understand the indicator well. Now I have a 15 minute indicator but I can't really predict which direction the candles will go next. For those who can predict the indicator correctly, a 15 minute, 30 minute or 1 hour indicator will bring good results on the trading platform. The trading platform does not seem very easy to me. The trading platform is very difficult but if you can gain experience in trading, trading will be easy.
Why will you use 15 minutes time frame to trade in the first place when you are not a 10 minutes perpetual trader, it's really risky because you will never see where there is major resistance and supports and also local resistance in the other time frame. Even if you are scalping, the best and least you can enjoy in time frame is 60 minutes and also 4 hours, you can use 8$12 hours for to confirm supports and resistance so you don't get caught up on your trade.
In a bull run, I don't advice people to scalp when the market is too good to be making profits. If you have been doing long term trading since October to now and you have been using high liquid pairs, the numbers of orders that you will have in profits to now will be far bigger than what you have lost because there has not been any major crash of the coin prices, if you have been doing only Bitcoin and USD pairs, you should be having high cumulative profits by now.