As far as I’ve seen, they don’t provide any advantage over a string with spaces, which doesn’t work well either when you’ve got values with spaces:
<span style="color:#323232;">not_what_you_think=( "a b" "c" "d" )
</span><span style="color:#323232;">for sneaky in ${not_what_you_think[@]}; do
</span><span style="color:#323232;"> echo "This is sneaky: ${sneaky}"
</span><span style="color:#323232;">done
</span>
<span style="color:#323232;">This is sneaky: a
</span><span style="color:#323232;">This is sneaky: b
</span><span style="color:#323232;">This is sneaky: c
</span><span style="color:#323232;">This is sneaky: d
</span>