What does Low risk vs High risk strategies mean in Ready made Option Strategies?

Upstox has separated strategies based on their risk levels. 

As per this - Bull Call Spread, Bear Put Spread, Long Straddle, Iron Condor are classified as low risk as the downside is limited. And Long Call, Long Put, Short Straddle are high risk based on the unhedged nature or high downside risk.

The combinations displayed for each strategy is filtered based on the probability of profit, moneyness and liquidity. About 3 to 5 pairs are shown to select from for an affordable and profitable trade.