Long vs short
A short costs you funding a long does not, and a spread every long ignores. The gap decides whether short is even worth taking on some markets.
Your two sides only look symmetric
Your long earns exposure times (mark − entry) ÷ entry. Your short earns exposure times (entry − mark) ÷ entry. Three things then pull the two apart.
You cross the spread twice either way
Your long opens at the ask and closes at the bid. Your short opens at the bid and closes at the ask. Any simulator that uses the last traded price for both sides is flattering itself. MarketMoves opens a long at the ask and closes it on the bid, and reverses that for a short, so the entry you see on a market page never matches the chart price exactly.
Shorting caps your upside but leaves your downside open
A fall of 50 per cent needs a rise of 100 per cent to undo. Shorting caps your gain at 100 per cent of exposure, because the price cannot go below zero, and leaves your loss open ended. High up the range that matters less than it sounds, because you are liquidated long before either end.
Funding usually charges one side more
Perpetual-style products pay a periodic funding charge between longs and shorts, and when the crowd is long, longs pay it. That charge accrues on your exposure, so a high multiplier compounds it against your stake fast. Hold through a funding-heavy stretch and it can cost you more than the price move.
Check both columns before you short
Across 45 markets here the biggest intraday drop from an open in the last 30 sessions reaches 11.42 per cent, and the biggest intraday rise reaches 15.30 per cent. Falls arrive faster and land closer together, so your shorts and your longs will not be closed at the same tempo even at the same multiplier. Read both columns on the market page before you assume a short is the safer way to hold the same view.