The Beluga is a highly capable ship, and I've taken mine on both of my lengthy sojourns outside the bubble - the first 5200 Ly out to unlock Professor Palin. The second, 6500 Ly out to celebrate the new and improved Route Plotting with Cone Boost.
If long range travel wasn't so tedious, I'd take it to the galactic rim - that 128 ton fuel tank is impressive.
Oh, and both trips I took a single, decent paying passenger in a single luxury cabin.
Plus all the amenities for exploration, and a fighter bay.
I also use one for bounty hunting, as 5 medium hard points are no joke (I run 3 PA's and 2 beams).
Even as a mining ship it's quite capable, being incredibly nimble for such a large ship.
I think where the real issue lies is in expectations.
Too many people think of these as Norwegian Cruise Lines sardine-cans for cramming as many people into every available space and charging a premium for enough room to change your mind.
They're not.
The Dolphin - This is a Maybach. Just a couple passengers and a whole lot of performance.
The Orca - This is a Limousine - bigger than it needs to be, look at me. You can cram a few more people in it and they'll still enjoy the ride.
The Beluga - This is a Yacht. It's massive, expensive, stylish, screams to be noticed. Sure, it has room inside, but it's not about quantity, it's about Quality.
You want a cram-packed Japanese subway style mass transit, complete with pushers to cram one more person on board, then fly an Anaconda, or a Type-7.
If you want a penthouse suite of 1500 square feet, with marble floors, down pillows, satin sheets and private cinema, then fly a Beluga.