I know you can get some big savings by buying via mail order but what happens if something goes wrong? I bought my cube eMTB from my LBS and it developed an intermittent fault after a few weeks of use. I took it back to the shop and they thought they had sorted it, but the fault returned a few days later. I phoned them up, they came to my house with a van and picked the bike up. Replaced the faulty part (speed sensor) and delivered the bike back to me, it has been fine ever since (over 4000 miles).
If I had bought the bike mail order how would I have got this sorted, I am not sure. I know if I owned an LBS and someone came in with a fairly new eMTB that they had recently bought from a mail order company and wanted me to sort out an intermittent fault I don't think I would be in much of a hurry to help them.