Side Scrolling Strafe Firing Feedback

So, I was considering making a side scrolling shooter where you can move independently of which direction you are shooting.

It seems to me that by holding down the fire button you could auto fire in the direction you are currently facing.  As long as you hold down the fire button no matter where you move you will keeping shooting in that direction.

Is that a good plan?  Would it eventually tire out your shooting finger?