Verticals trade off unlimited upside for defined risk and lower cost. A debit-spread pays to enter and profits from direction; a credit-spread collects premium and profits from the stock staying away from the short strike.
Maximum loss and gain are known at entry, which makes verticals the standard way to express a directional view with options without excessive theta or vega exposure.
Example: buy the $100 call for $5, sell the $110 call for $2. Net debit $3 ($300). Max profit is the $10 width minus $3 = $7 ($700) if the stock is above $110 at expiration; max loss is $300.
Related: credit-spread, debit-spread, iron-condor, strike-price