this question is asked quite often.
slide supports are holdovers from the early days of slideouts.
now, the technology doesn't need them, in fact you should have something posted or in your manual, warning you NOT to use them.
most manufacturers will void the warranty if you do.
there are many threads about this on the forum.
a simple search will give you lots of reading on the subject.
and Zoe the Wonder Dog(R.I.P.)
'07 Roo 23SS pushing an '07 Chevy Avalanche
Equalizer WDH and Prodigy BC