I suppose it depends what SALT needs you are talking about.
If a child has specific trouble with sound recognition or sound formation (not being a SALT I don't know the specific terms, sorry) then I can see that specific SALT sessions can be useful.
However, with a child who has generalised S&L delay, along with attention difficulties, etc., so much of their problems with language and speech are underpinned by a delay in the acquisition of 'pre-learning' skills.
For DD1, you could tell her til the cows come home that it is 'BA - NA - NA' not 'MANA', but she a) doesn't even recognise that she is saying 'mana' b) doesn't seem to hear the difference between 'mana' and 'banana'
She needs to work on pre-learning skills like sharing attention, joining activities that an adult chooses, listening to instructions, listening to explanations, etc.
What use is an hour of 1:1 SALT to a child who cannot even sit still for 5 minutes, and doesn't give two hoots whether you say 'mana' or 'banana'?
It took me a long time to come to that conclusion, but having seen the hours I spent in a SALT room with a SALT who wanted DD1 to sit at a table and read a book, when DD1 wanted to look at the trees out of her window, or the toys up on the shelf, I could see that it was doing nothing. The one useful session I saw was when I took over and said 'OK, what about 1 think that wants to do, then 1 thing that wants to do?' Finally the SALT saw some language.
The SS environment means that for DD1, the teaching staff can capture SALT opportunities during any activity DD1 is doing. Extending language, adding content, clarifying pronouciation, etc.
I have tried it as I typed:
Me: DD1, say 'banana'
DD1: 'Mana'
Me: 'Banana'
DD1: 'Mana'
Me: DD1, BA - NA - NA
DD1: BA............ 'mana'
There are so many words in her vocabulary that are 'wrong'. she says 'armti' for 'aren't I?' she copies phrases adults use, but she hears them differently to us, I think.