D&D 5E The Rogueish Shenanigans!

[Blackbrrd]

Bless is an average +2.5 to attack (and can be interrupted), which means it only makes up for half the penalty. Not "quite easy". A -2.5 to attack is bad. I am betting you wouldn't be calling a cursed axe that has a -2.5 to attack "quite easy" to attack with. It's a 12.5% decrease in attacks. That's bad. Now if you can get advantage, that would in fact cancel out the -5. Hence I mentioned the halfling rogue archer attacking from hiding behind his ally.

-2.5 in attack is often closer to -25% chance to hit than -12.5%. Example: +6 attack vs 15 AC = hit 10 out 20 times. If you have +3.5 attack vs 15 AC = hit 7.5 out of 20 times. You're only hitting 75% as often!

For the -5 to hit/ +10 damage to be good, you are at break-even if the attack penalty halves your chance to hit while the +10 to damage doubles your average damage. This doesn't take into account over-killing or that high variance is something you usually don't want as a player.

In other words, it's usually best to use the -5 to hit / +10 damage in a situation where you have advantage, buffs that increases your to-hit chance or when fighting really low AC opponents/high HP monsters. Zombies comes to mind.