does google max performance matter for a small site?

Guessing you mean Performance Max? For a small site, probably not yet. One PMax campaign runs across search, youtube, display, gmail and maps and the algorithm decides where the money goes, so it needs conversion data to learn from. On a small budget with a handful of conversions a month it can spend a lot on cheap display placements. A plain search campaign on your best keywords is easier to control. Try PMax once conversion tracking is solid and conversions come in steadily.