Is robot mop do anything? If so, help to decide on the best one

Hi Thalia

Most robot vacuums that do both mop and sweep will not replace manual mopping (or using motorizing devices such as cordless wet mopping cleaners or electric mops) however, don't let it stop you from getting one.
Those robot mops that are equipped with a container and mopping attachments and drag the mop around the floor would most likely not remove stains but they are great helpers in terms of prolonging the time between big mopping jobs. It is more convenient to install the water container and let the robot run around while you're not home or minding your business (do not forget to set restricted areas around carpets though). I use mopping when having no time for mopping or simply lazy to do so and it's helpful since it leaves floors dustless and gives me some more time before I do manual mopping (I actually use an electric mop which I would recommend to anyone who still does it manually).

About your question. There are some robot mops that are more efficient than others. This list includes (imho) the Viomi V2, Xiaomi MiJia STYJ02YM, iRobot Braava m6, iRobot Braava Jet 240, ILIFE W400, and maybe the ILIFE A9S. Let's quickly go over the pros of each:
Viomi V2: follows a Y-shape when does mopping. It allows the robot going over the same spots a few times so it is able to remove stains which it did base on our tests we put the robot through. Plus it has a big container and is efficient when it passed around one room three times, it still had 80% of water inside.
Xiaomi MiJia STYJ02YM is very similar to the way the Viomi V2 does mopping. Also follows the same pattern and has a big water container.
iRobot Braava m6: has a system that sprays water on the floor tucking stains in order to soften them so the robot removes it easily. One downside of this: the Braava m6 does not do sweeping though it is suitable for big homes.
iRobot Braava Jet 240 is perfect for one room or small apartments. It has a vibrating head which does movements removing stains.
ILIFE W400 is also an only mopping robot. It is equipped with two large containers for clean and dirty water and is suitable for bigger areas. It has a soft roller that scrubs floors when moving. It is tall and would not get under some furniture but is a nice and budget machine to get if you need a cleaner that only mops.
ILIFE A9S is not the best robot mops but it can do mopping and sweeping and has a vibrating water tank that gets close to the ground and repeats the way a human mops.

That's being said you can get a good robot vacuum that will do mopping and maybe even buy one that can replace manual chores. If you decide to go with the one I would recommend any of these models above.