The mechanical effect
At 1:100 a standard lot of EURUSD needs roughly one percent of notional as margin. At 1:500 it needs a fifth of that. Profit and loss per pip are identical in both cases.
Where the danger is
High leverage makes oversized positions possible, and oversized positions are what damage accounts. The risk lives in position size, with leverage acting as the enabler.
Choosing a level
Pick the lowest leverage that still lets you open your normal position sizes with comfortable free margin. That single constraint prevents most catastrophic sizing errors.