Really depends on market and competition. I've seen several IBA additions and I think it's important to drastically change the exterior look of the building to get the attention needed by those passing by.
Also, IBA operations offer different challenges than a self serve, so it does change the nature of the business somewhat. I'm getting ready to retire and would love to have a high volume self serve only wash, which I could run in my sleep. If you have a self serve bay go down, no biggie. I feel compelled to drop what I'm doing to go get the IBA running
I will also add don't be afraid of a modern soft cloth units that has torque sensing abilities. Damage claims are almost non existent and the cleaning is consistent. But again that depends on your surroundings. If you are surrounded by touchless units, consider cloth. If you are surrounded by cloth units, consider touch free.