Can i ask for refund? Plugin is useless for me.
1). It is adding messages in wp-posts table. I’ve 10,000+ users and this has made wp_table size over 500mb in just one day. Slowing down my entire site. It should have been in separate table.
2). Duplicate meta_key participants.
Your plugin is adding duplicate meta_key for each user. This is not a best practice and is creating errors with my custom codded message plugin.
Answer of your question
1. wordpress tables are highly optimized and we can use all core functions for those tables. You can google, you will find hundreds of reasons to use wp table.
bbPress uses wp tables. wordpress.org use bbPress as their support forum. Do you think you have more users and more messages then that support forum?
2. it is always better to use equal ( = ) query then LIKE query. we can easily use equal query if we use duplicate meta_key. Also wordpress support duplicate meta_key. So if your custom coded message plugin shows error for this i think you should change code of that plugin so that it does not show error.