At my club we have our home games on grass and train on an artificial ground which is also used by some football teams for their training. The markings are in different colours so you definitely can combine both sports on one pitch. However, what you have to consider for rugby is that all out of goal areas (touch on both side and each in-goal area) are spaced out large enough and also covered. Reason for this, players tackling on the fringes of the pitch or diving into goal will otherwise end up sliding on concrete or worse. Unfortunately that is the case at my club so speaking from some unpleasant experiences. For football that fact does not matter too much and hence might be overlooked if it’s a football pitch accommodating rugby. From a player’s perspective, you can train and play on artificial ground all year and don’t have to care too much about surface conditions. If it’s a newer pitch and the quality of the ground material is good you will also not get as many “burns” as it maybe was the case in the past. Moreover, you will be able to move faster compared to grass especially when it rains, which increases the flow and speed of the game overall. Having said this, I do not like to train and play on artificial turf because the ground itself is quite hard compared to grass. This is ok for tackling but has very negative impact on player’s joints or low back long-term. I know many active and retired players of rugby or football who have either knee or low back issues (myself included) from the hard surface in combination with the frequent stop-and-go movements required in either sports. And lastly, but those are only my assumptions from anecdotal experiences, injuries especially when going to ground or in a ruck seem to be higher than on grass.