Feed our ego, put money in the meter...tell your friends...
IMDb credit for work instead of pay is one reason why IMDb is losing is value for casting and for actors.
There is no guarantee or quality, professionalism, or that you even filmed the role from an IMdb credit, not anymore. Too many "credit for work", background making up characters, ultra low films never completed, poorly acted films and publicist working to build your IMdv cume (whatever that really amounts to).
Background is not a role (from the accepted Hollywood view) and non-paid is community theater as far as those casting are concerned.
Think like them.
Think like the casting director who wants experience, talent, the right look, the ability to be on time and do the job from anyone they hire...and whose job is to provide what the director wants for the best possible product.
The other reason is that since Amazon purchased the Breakdown Services and the Internet Movie Database it has been about volume not quality, charging actors, not making money from agents and producers,and selling videos and on-line services rather than service for the industry. Their focus is the general public, fans and actors and not the producers, casting directors and directors they once served. Check your history and talk to those who were involved.
Many actors have had credits removed by choice because IMDb also betrays your age and in doing so limits your potential roles.
Some actors have credits removed by IMdb that are recent and legitimate. It is almost impossible without a copy of your contract to get them restored (always have a contract, preferably a union contract).
Spend your marketing money where you will.
I am not saying IMDb does not have value for the actor or the consumer. It does.
So do other pay services and so does your own elbow grease and shoe leather.
Spend your marketing money wisely, and be sure to follow-up and remember that, whether or not you have an agent, whether or not you have a manager, you are, in the end responsible for building and maintaining your own career.