Short: it improves by a lot the readability of your text.

Sentences are one of the most important tools in language to organize ideas. A dot is too small and discrete to set apart sentences. Adding a dot ~and~ an uppercase letter right next to it makes a much better separator.

You're welcome to disagree. Since you were generous contributing about spelling - I'm not a native English speaker, btw -, I just wanted to pay back with a suggestion about text structuring and readability.