Here are some points, when it is useful to have contacts with your own "community".
1. When comparing and understanding systems (for example you go to drive test center to get your driving licence, but you go to Service Ontario to exchange it. But in your country it was different. So when somebody explains you that it is advantageous).
2. When doing some specific tasks that includes proper paperwork from your home country (for example first year taxation, education documents for your children and such. Then again it is good to know, if somebody can help and advise you.
3. Meals from your country. More like where to get same or similar ingredients if you want to cook it here or where to go, if you want eat it here. Just remember in both cases it will not be the same (especially restaurants have to set up for local taste, so your food might not be as spicy, sweet or salty as you were used to).
4. Getting more news about your old country. This one is more or less obsolete with the age of internet and easy communication. However it can be still refreshing to know what is happening at home.
And here are the points why it is it not so good to live in your own "community"
1. Language. The more you use your language and the less you try to use English or French, the more difficult is it to improve. And even if you have received high score in the language test, most of you have accent. And unlike to be able learn proper grammar or to learn to pronounce somewhat decently, accent is the last to go. And the best way to get rid of it is listen to locals as much as possible and try to mimic their speech. So the less you are doing it the longer it takes. And that at the end is burden. Nobody might tell you that, but there are professions where too strange accent is a burden. (handling important clients with thick foreigner accent might hint, that your company is outsourcing abroad, but not always with best quality in mind. Dealing with small children like that is rather no go. And even is some positions of doctors or lawyers, that is a hindrance.).
2. False comfort zone. You will stay in your own culture which seems to be good but it is bad at the same time. It so happens, that when you meet the new culture it mixture usually has parts that are better than what you know and part that might be step back for you. Without much willingness to learn how they function, you will keep all the weaknesses of your own culture and you would hardly try to improve it. Why? Because that is what you know already. Implementing the better parts for you and in terms offering what is better for them will be beneficial for both side.
3. We and they syndrome. When you are enclosed in your community, you see yourself outside new country. Then you think of your new countrymen as "they" rather than "we" and again it takes much longer to switch to the we thinking if you decide to party separate yourself from the rest. As a result loyalty is lacking when needed. Because it takes that thinking of we wants to be better we want to improve as a country for the country to slowly improve.
4. Limited options. If you go for living in your own community, you are limiting your options. Starting with area where you want to live, or what services to use and whom to meet with.