Don't just say "DO IT" just because
Look at the numbers and analyze instead of just saying "IT'S WORTH IT JUST DO IT".
It's a sign of doing things out of ignorance.
From an Economic prespective it is totally NOT worth it.
Not only it cost ALOT of elixer (7.5mil) look at the price efficiency.
You get a 10% damage (from 20 to 22) and 10% health increase (from 40 to 44) for the price increase of 50%! (from 200 to 300).
If you are farming for it is easy to see that the return is not justifiable. You will save more elixer from raiding using level 5 archers just because of they are much cheaper than the level 6.
IF you are going for trophies however, then you're probably at the stage where price does not matter as much. This is where it would be good to get this upgrade. With that said by that stage you will probably rather use wizzards or higher tier range units.
They Supercell should really increase the damage and health gains by another 5% for this upgrade to be viable. Sure the archers look cooler, but they really aren't worth it from a cost to gain point of view.