My best friend is a house call vet; I wouldn't do it for any amount of money in the world, but it suits her. However, she does not work for a company - she has her own license as a house call practitioner, finds her own clients (and gets referrals from other clients or clinics), keeps her own supplies and records, etc. She is also associated with (but not employed by) several different brick-and-mortar clinics to whom she refers patients for work that she cannot do in a home, like taking rads or doing surgery, etc; without that she couldn't legitimately (or legally) practice. It's a niche market that involves A LOT of traveling time, and often what I think are uncomfortable working conditions (doing exams on the kitchen table, or in a room with poor lighting, etc), but it allows her to do a lot of palliative and end-of-life care, which is an area she likes because it can build very special veterinary-client-patient relationships.
If you're talking about companies like InstaVet, Vetted, or Kwik Vet, I think they are a pox on the industry, turning medical professionals into overworked freelancers in the gig economy. I would be concerned about my safety, going in to strangers' homes alone (or working with an unknown technician) just because someone registered on an app. And a bigger concern is that many of those companies are started by and run by non-veterinarians, which I think is a big mistake whether it's a brick-and-mortar practice or a house call practice.