It depends how much it is. Let's say it's £500. You could take the motor wheel, LCD and battery off, install a nice Chinese kit for about £600, then you'd have a nice electric bike for about £1100.
Seriously, that's the second time that it's appeared here in the last few days. It's a nice Trek bike with a Bionx kit added. When the Bionx works, it's not bad, except that it's a direct drive motor, so it doesn't freewheel like a geared motor, which some people don't like. The main problem is that you're locked out of fixing anything by the software, so you can only get it fixed and buy spare parts from a Bionx dealer if you can find one. If the bike has been used, the battery would be worn down a bit. who know how far? You'd have to pay the price of a complete e-bike for a replacement battery, though it's possible that BGA Reworking could re-cell the battery. Unfortunately, he wouldn't be able to test it without the rest of the bike.
For me, it would be too risky, but for £500, you'd have the option of what I wrote in para.1 when it packs up. Any more, and you're gambling on how long it's going to last. I'd need a lot more information before I could say how long it's likely to last.