When I built my affiliate business I came across a unique problem. It was in 2012 and I was starting to build out affiliate sites in my native language German. I started off with hosting all my sites on Hostgator, since I had a cheap shared hosting account I just added all my sites to. However, I soon realized to get serious about the German market I had to find a host with servers in Germany.
The main reason was to be closer to my visitors. It is in general better to have your server in the location you are targeting,. This is also rumored to be an SEO advantage, however I have no clear evidence of this and have been able to rank German sites hosted on US servers just as well. Additional .de domains have specific DNS requirements that German hosts naturally fulfill, since they host a lot of .de domains.