100x yes.
1) you can pre-pay for your checked baggage. if you pay at the airport, i believe it costs $5 more per bag.
2) you can print your vouchers, so when you get to the airport you just have to scan them at the self-automated kiosk. then you check your bags and wait through the security checkpoint.
3) if you cant print your vouchers - no worries! just slide the card you purchased the tickets with into the kiosk at the airport and it will re-print your boarding pass.
i love checking in online