Should I check in online if I have to check baggage anyways?
 

I understand how checking in online before your flight is beneficial if you only have carry-on luggage, but does it do any good to do it if you have to stand in line to check your bags anyway? I know sometimes there is curbside check in, but if not and you are already checked in and stand in line to check your bags, are the agents going to make a big deal about how you are standing in line when you already checked in and have your printed out tickets?

Yes, you should. On airlines that offer seat assignment, checking-in and printing your own boarding pass secures that assignment. Also, many airlines at many airports have separate bag drop-off lines that are separate from the regular check-in lines. And with BP already printed, you also save time you spend at the counter dropping off your bags.

Agents definitely have an issue with you. In fact, most travelers with bags to drop will do the same, already checked-in with BPs in their hands.

Also, you may save a dollar or three on the bag-check fee (if you are subject to one) by paying it online at the same time as the check in.

Yes you should.
No the agents aren't going to make a "big deal" about it.

Its always faster in all of the international airports that I have been in!