Going from eight to ten decks is very marginally good for the Player bet, decreasing the house edge by 0.0014%, from 1.2351% to 1.2337%. It is slightly bad for the Banker bet, increasing the house edge by 0.0012%, from 1.0579% to 1.0591%.
It has a bigger benefit on the Tie bet, decreasing the house edge by 0.0477%, from 14.3596% to 14.3119%.
However, the biggest benefit is on the Player and Banker Pair bets, decreasing the house edge by 0.5349%, from 10.3614% to 9.8266%.
For more information, please see my page on ten-deck baccarat.