depends on how much money your character has.
Generally Bards aren't as hard pressed for action economy as Wizards. Still action economy is hard to get in the game and it's not a bad deal especially by 10th level. Just make sure you don't create a log jam of actions that are swift, and make sure to talk to your GM so you are not forced to use the singing steel armor with your bardic performance (keeping it a move action).
The problem with singing steel is that it doesn't work well given the price, wealth by level, and the ability scaling of bards.
Basically- By the time that the cost is not a major burden, you will be close to getting swift action performance anyway.
Additionally, I am not sure bards really even need it. Bard action economy has always been a strong suit of the class (at least at the levels where you can afford this thing)- they can do performance and a spell on the same turn for two buffs. Since your common buffs spells (like haste) usually take up a lot of your turn, you are not using that move action for much else.
There might be circumstances where having the freed up move action could be useful (maybe moving back when you are ambushed, or getting up when knocked down), but that isn't really worth the price and the side effects on your weapon (sure, it also counts as alchemical silver, but mithral does the same thing and it is usually cheaper).
Its only 3000gp for a msw tool to aid you in your performance that doesn't have to take a slot. Beard bells or dangling wind chimes to help your performance sound more magical come to mind. It is fairly worth it before level 7 in your first round. Move to sing and a standard to cast a spell (great for buffs like mirror images or utility spells like glitterdust). Also if you are a selfish archeologist or dervish dancer bard it goes from a move to a swift prior to level 7.
It's also good prior to L7 when you don't have an iterative or lingering performance because it allows you to start it up, 5ft., then still get you one attack and you don't have iterative to lose if you're not an archer. Helps pump out saving finales as immediate actions.