We have done East coast of Baja and west coast of Mexico for the last 6 years part time. I would say PB are 1to 25 or 1 in 50 there. You see them more on the smaller boats and seem to work well.
I have a rib and run a either 2.5 hp or 10 hp. and that work well for me. When traveling the motor comes off the dink. So if we are just going to shore or to another boat the 2.5 is used, if doing some distance the 10 hp comes out. If "I" only had 1 motor "I" think that "I" would want at lest a 5 TO 6 hp on the PB. It going to be different for each person. Not very many people drag their dink when traveling, they come out of the water. At night most lift the dink on the side of the boat. The halyard on the side of the boat can be used.
We do a lot of swimming and it is nice to have a way to get in and out of the dink away from shore. Going to shore is a pain to get in and out of the dink. Even a RIB with 16 inch tube can be hard.
The best beach landing that I have had is in a 20 foot panga ( I was not driving, that may of had something to do with it), A lot can be learned from them. He backed in. It did not seem to "rigid". I would not of wanted to land the RIB that day.
We have wheels on the back of the dink so when we hit the beach we can get out fast and pull the dink out of the surf fast. It nice to be able to be able to pull the dink above surf line on calm days too without needing 4 people.
Bottom line, you do not know if the PB will work, Do you know what inflatable would work better? There are places in Mexico to buy and yes it may cost you $500 more then the states but it will not be a $3000 mistake. and who knows the BP may be the dink for you.