Special issues are usually thematic and focus on one narrow topic or subject. They are likely to gather more attention from readers and researchers. There is also a possibility that the manuscripts published in the special issues will have more citations.
If your article is focused and as per the theme of the special issue, it might be easier for it to get published in the special issue rather than a general issue
I am an invited guest editor and regional editor for two different journals related to special editions that will come out late this year. Awais - it's not about 'prestige'. A good journal is a good journal - regardless of a special edition or not. Of course, a special edition manuscript submission must fulfil the topic scope and criteria. It could get cited more than a 'normal' issue - but depends on the topic. Of course, let's take Covid-19 issues as a special edition consideration for many journals at the moment. It depends on specific timing and topic - as to if such editions will be more cited than a regular volume.
I agree, no clear difference in prestige, but possibly in likelyhood of becoming read and cited. Another characteristic I appreciate with special issues is the time perspective; you either are accepted for this issue or not within a clear time plan. The journal cannot first accept the article and then postpone publication to later as sometimes happens with regular issues.
There is no difference between special issues or regular issuer. Some journals will arrange for special issues, 3 or 4 per year. These special issues each has a specific theme (cover research on a topic), and a guest-editor or two are responsible for defining the topics, inviting authors, organising the peer-review and making decisions about the submissions.
Different journal may put different meaning into "special issue" It could mean that papers have been invited around a certain theme, it could mean papers come from a workshop or symposia, or that the journal have decided to gather papers around a specific topic for some reason. The point is that a special issue differs from a regular issue in that the papers constitute a collection around a theme or coming from a specific group of authors or event. Such issues can either be a decision by the journal or a request from a group of scientists to publish around "their" proposed theme. There may be additional cases but these are the ones I am familiar with within my field.