How to get compliments in Pokémon Legends: Arceus
Not everything in the land of Hisui can be bought with regular currency. Some items, including rare gems and items necessary for Pokémon evolution, can only be purchased with Commendation Points.
Reward points are a new currency in Pokémon Legend: Arceus that is only given to complete a particular type of task. If you want to get lots of evolution items to maximize your Pokédex or make your team as strong as possible, you’ll need to get Bonus Points.
How to get compliments
Merit Points are only awarded when lost bags are found throughout the wilderness of Hisui. These satchels belong to other real-life players who have been defeated in the area. Interacting with the bag completes a quest, which grants a different amount of Rewards Points depending on how many items you rescue. In general, you will receive between 50 and 100 Merit Points for each bag returned. You will also receive an item as a reward, possibly something special, such as a consumable evolution item.

Merit Points can be exchanged at Trading Points for a variety of items, many of which are disposable items needed for evolution. Because of Arceus no longer includes a hold item mechanism, items that previously needed to be held while trading a Pokémon, like the Magmarizer, can now simply be used on a compatible Pokémon to initiate that evolution.
The more Reward Points you get by rescuing satchels, the more items you can buy.
https://dotesports.com/pokemon/news/how-to-get-merit-points-in-pokemon-legends-arceus How to get compliments in Pokémon Legends: Arceus