However, I have gotten tired of dealing with my tea ball infuser at work. It's just too messy.
I have a collapsible silicone tea infuser which is really easy to work with, you pour the hot water over the funnel, and then you dump out the tea leaves once you're done with them. I think this would be much less messy than reusable bags, and less fuss than the tea balls.
Your silicone infuser does sound nicer than my current tea ball :) But I don't think it would solve my issues with having an infuser in the office.
My issues are: (1) loading the tea leaves into the infuser is a bit messy in a dry way, and (2) unloading used leaves out of the infuser is a bit messy in a wet way. My office kitchen is a pain to get to, and I already tote a lot of mugs and bowls back and forth to fill then use then clean, so I have just been filling and emptying my infuser in my office. At some workplaces, I would feel comfortable doing so, but it just doesn't fit in with the culture of my current environment.
My thinking with reusable bags was that I could fill them at home, use as many as I wanted in a day, and then refill them at home. So all the messy parts could be done at home.