Economically a married put has the same payoff as a long call at the put's strike: unlimited upside, floored downside, with the put premium as the cost. Buying both legs together is what distinguishes it from a protective-put added to shares you already own.
The reason the distinction survives is tax. In the US, a put bought on the same day as the stock and identified as a hedge can preserve the holding period of the shares, while a put bought later against an appreciated position can suspend it. Confirm the treatment with an accountant rather than a forum post.
Example: XYZ at $50. Buy 100 shares and the 90-day $47.50 put at $1.35 as a package for $51.35 net. Below $47.50 your loss is capped at $3.85 a share. Above, you keep everything past $51.35, which is exactly the payoff of the $47.50 call plus a bond.
Related: protective-put, synthetic-call, collar, left-tail-hedge