Unless you’re one who needs to distribute HD footage, I certainly agree. 
The cheapest Blu-ray media I’ve come across on a UK online store (7DayShop) is £15 for a 10-pack of Ridisc brand BD-R media, which works out at 6p/GB
On eBuyer UK, I came across a 1.5TB Samsung external for £90, which also works out at 6p/GB.
So at a first glance, BD-R seems to have finally caught up with HDD on a per GB price, although some will think twice of Ritek BD-R media.
[B]Unfortunately for the BD-R, we’ve run into multiple problems: [/B]
[ul]
[li]The BD-R media requires a Blu-ray writer before it can be used, where as the USB drive is just plug ‘n’ play. [/li][li]For carrying data on the move, the user will either need to have a BD-ROM drive where the BD media will be used or carry an external BD drive to read its discs. Again, a 1.5TB USB drive is just plug ‘n’ play.[/li][li]1.5TB on BD-R works out at 60 discs. Unless kept on a spindle, these discs would take up more physical space than a 1.5TB external drive.[/li][li]For backing up a significant amount of data, the user would need to be present to load each disc in succession. For 1.5TB of data, a 1.5TB drive can be left unattended (e.g. overnight backup), where as with BD-R, the user must be present to load & eject every one of the 60 discs.[/li][li]In the event of a disaster requiring recovery of all the data, the BD-R recovery process would involve manually loading and ejecting all 60 discs, where as the 1.5TB drive could also be left unattended for most of the restore process.[/li][li]BD-R media is not rewritable and BD-RE media costs a lot more.[/li][li]With the 1.5TB drive, you have direct access to everything. Not so with 60 BD-R discs.
[/li][/ul]
Ok, some may argue that storing 1.5TB on a single disc creates a single point of failure and this indeed is very true. Well for the cost of the BD writer, consider getting a BD-ROM drive instead and use the saving towards a second 1.5TB drive. Make a periodic mirror and keep the second 1.5TB drive off-site.
On the other hand, at least BD-R media is finally coming down bit by bit. Unfortunately for Blu-ray, I would imagine that by the time the media and drives become as affordable as DVD, flash media pricing will not be far behind. Even today, you can pick up two or three 32GB USB pen drives for the price of a BD writer. 