MetaTrader demo data is often or filtered to look pretty. Dukascopy data is raw. Real FX markets are noisy. If you see small spikes (1-2 pips) that reverse instantly, that is actual interbank latency arbitrage or stop hunting that occurred in the real market.
On Christmas or New Year’s Eve, spreads blow out to 50 pips. If your backtesting script doesn't account for spread widening, it will show false losses or false profits. dukascopy historical data
Tick data allows you to simulate trades with realistic fills. For example, a scalping strategy on EUR/USD can be tested for slippage during high-impact news events (e.g., NFP releases) using 2009 data. Unlocking the Markets: The Ultimate Guide to Dukascopy
Traditional Open, High, Low, and Close prices available for timeframes ranging from 1 minute to 1 month. Storage Structure If you see small spikes (1-2 pips) that