BTW, You dont need paypal to get it.
Click the donate thing on Titanium Backup Program.
Paypal will act as a middleman for your CREDIT CARD.
Safe and easy.
Did it yesterday, and within 10 minutes i had my "Pro" email.
As for the usefulness? If you backup 100 apps having to click install every time is ANNNOYING. Well worth 4 bucks to avoid that pain! Plus its faster backing up too, so really a small price to pay for your time.
Also, the program is pretty awesome, so well worth supporting the developer.