My leg is killing me so I've had a large quantity of about 3 different opiates.
I used a supermoto all year round for nearly 2 years doing 70 miles a day, every day even in winter through snow. It's an expanding market in the UK according to Suzuki UK who admit they don't have a bike to meet the increasing demand. They are not slow - they don't have high top speeds but they're all about low end torque which makes them brilliant for commuting and they offer excellent handling and acceleration within legal speeds and for commuting.
They are a bit vibey, but the suspension soaks up all the potholes Yes there are racing set up ones which are uncomfy and designed for tracks but that's a very specific market. Some people find the seats too small, but that's mostly because this country has got fat. Expensive to run? My DRZ was the cheapest bike to run I've ever had.
Supermotos are small, light, handle ridiculously well and are damn cheap to run and cheaper to crash. You pay maybe £20 for a fairing. The lightness means fuel economy is good also, making up for the small tank.
Yes they can be a bit vibey, but I never had a problem with it. This, along with the lack of weather protection are the only two downsides.
If you personally don't like them that's fine, but there's no point in trying to outright rubbish someone else's opinion / insult them just because you don't agree.
In my opinion, there's little less pointless than a 190bhp supersports on the road - they're designed for the track but if people like to ride them on the road that's up to them. I can see the appeal.