Hey..here my 2cents:
yes i use it but not for my choice...i got 2 shops some years ago using this module ( they were built with ps 1.6..and now i have migrated them to ps 1.7 with the same module)
Benefit for seo?: i would say that there is a relative benefit for seo because the url is the last thing that Google check to give you a ranking..i mean that there are other aspects that are more relevant in ranking attribution process
Installation and use: well i've never had problem in installing it or unistalling...but you have to follow the extact procedure. I've never broken any shops with that module...of course you have to disable cache e copy somewhere the original path because you need it if you decide to not use the module anymore!!....no problem at all.
Collateral effect: well here comes the problems....you are forced to use for example only some Blog Modules..other don't work....Some Reviews modules don't work...rooting goes belly up and pages responce stick on 404...but i solved this using a particular module.
The main problem is that the default automatic redirection when you change product name is Kaputt!!..so you need a third party module to manually create a redirection otherwise you get 404 on that products.
Bottom line: if you are bulding a new shop, or you have a production shop i suggest not to use it...pain does not justify the benefits!!...maybe it makes sense when migrating from platforms as Woocommerce or Opencart to Prestashop ( those platform don't use id in url) ..in that case you should be forced to redirect every single no-id url to id-url..so maybe this module can help because it maintain old url structure.....
ciao!