eBay's search will treat certain punctuation marks between keywords such as a period, dash, asterisk or underscore as equivalent to each other or to a space.
It may not matter inside parentheses, but if you want to search for a phrase rather than individual keywords, linking them with periods rather than spaces can be useful, since ordinarily eBay considers keywords separated by spaces to be individual keywords that can appear in any order.
Using periods between keywords can allow for keyword substitutions of other search keywords. Using quotes or other search commands (like parenthetical "OR" terms) prevents any keyword substitutions.
