Naturally it's cheaper, does the same job, but is it faster? Not at all. Imagine having to walk back to your bucket every time you need to get your sponge. It's like you are thrown back to 100+ years a go.
Even if you have it on you at all times using your applicator will be faster. Granted normal sleeves are not great for fly/spider poo, but the porcupine is great for it.
Not sure if you were serious about cost, but if you can afford a T-bar, you can afford a sleeve?!

The sleeve lasts for ages, I think I used my first one for over 2 years. T-bar is pretty much a one off investment, one that you would need to make anyway when window cleaning.
Sent you an email.