Doing studio portraits on location means that you have to tear down your lights, backdrop, stands, cameras, etc. and pack them in your car. When you get to the location all that equipment has to be assembled and the process has to be repeated when your done. Having portable studio lights makes life easier.
I do have 4 regular studio strobes. The power packs are self contained so they are heavy which requires heavy duty stands. I love them in the studio but not to pack them up and transport them. For ease of transport I have Novatron lights. Novatrons like Speedotron, and Dyna-lite are portable flash units that are made for location photography. They are compact and made for travel. There are other brands but these are the ones that I am familiar with. They are powerful and durable. I bought them over 20 years ago and they are still going strong. A complete kit that has four lights, a main power pack, umbrellas, stands, and carrying case to put everything in goes for about $1,400 to $1,500 dollars. Some cases have wheels to make your day sweat free. All for less than the camera you own and they never get outdated like your camera. They are the best investment you could make.
I use them for location portraits and commercial jobs. You can also purchase soft boxes and other attachments separately.
Being able to take your studio photography on location is a big plus.
The quality of your images remains constant.
If you do on location studio work portable studio flashes are something you should try and invest in. They can make life a litlle bit easier.