The reasons could vary depending on which team will win the match, but I see it differently, as there is a possibility of a draw, reminding both teams that they will be cautious enough to avoid dropping points.
One striking difference between the 2 teams is that Liverpool have conceded 4 goals, while Arsenal haven't conceded in their previous 2 matches. Both teams are performing equally well in attack, although Saka was absent from this match, but Arsenal still have reliable substitutes.
According to the bookmakers, Liverpool are the favorites, most likely because they are playing at home. In the previous match, Liverpool hosted Bournemouth and conceded 2 goals. Therefore, a draw is still possible, but the best betting option is most likely BTTS.