Depending on how specific the injection needs to be, there are a number of scenarios in which people can self-administer injections. So, ignoring people who physically can't self-administer, it isn't that dramatic a change.
I can't help but feel that the professional would be even more necessary to administer this correctly and not just waste a treatment/dose doing it wrong, whilst under the illusion that you did it right. Along with the specialised equipment needed for it in the first place. Needles and doses at least are pretty easily self-contained and if it is suitable for self application just "pointy end goes in fat bit of you".
Naturally it's early days, so it'll be fascinating to see how this develops.