Is there any real difference between these two? Wouldn't using the odds for the next card only plus factoring in implied odds be the same as effective odds?
No. You are two confusing separate ideas.
Implied odds are what you can expect to make if you hit (which might be zero, if you wont get paid when, say, the easily seen flush card hits).
But using what you are calling "effective" odds (if I'm understanding you here), you are NOT factoring in
the PRICE you will have to pay on the turn (in NL, typically at least half the pot or more).
When making a
gambling decision you are comparing the price to the odds of the event occurring. So you compare the amount you can win to the amount it will cost you, then compare that in turn to the chances of the event happening.
Simply put, "implied odds" can make your money odds better, but it isn't necessarily correlated to the "effective" event odds (which don't change, you are 2:1 to hit your flush draw by the river if using a fair deck).
Let's say you and your opponent both have 1000 behind in your stacks after the preflop betting, and there is 200 in the pot. Your opponent bets 200, so you are getting 2:1 on your money. If you have a flush draw you are 2:1 to make it by the river. However, you are not 2:1 to make it on the next card alone.
If you call, the pot is now 600, and you each have 800 behind. Now your opponent bets the pot again (600), giving you 2:1 on your money again. You call, pot is now 1800, and you each have 200 left. Say you hit your flush on the river. Now you can win only the 200 that is left.
Your "implied odds" on the flop
might be enough to call (assuming he will pay you his entire stack on the turn/river). However, when your opponent bets 600 on the turn, and has only 200 behind to win, so your implied odds are not very good.
If you call both the flop bet and the turn bet, then you have paid a total
price of 800 (200 + 600) to win 1200 (initial 200 pot + 1,000 behind):
that's only 3:2 money odds on a draw that is 2:1 event odds to make.
(note that you may be able to call on the flop due to implied odds alone, but thinking that you are calling because of effective odds isn't correct).
In other words, effective odds are only good in all-in situations, where you know the total "
price" up front.