cTh is a eTe?

[Bluetoes101]

Some say the dashes make a letter a capital

I believe this is for being able to distinguish them in transliterations (also works well for custom fonts) rather than actually being a capital letter

cth cTh
cth    cTh

Personally I don't think both sides are "e", because "ete" is fine in "what follows what" according to my research on it, also "ee" is fine. 

My personal (unsupported) theory is that it might be "ae"
1. "ae" is mostly not a valid pairing 
2. "a+gallows(+e)" is mostly not a valid pairing 
3. "a+s(+e)" is mostly not a valid pairing (Sh)
                                                            
I think pulling this final line of "a" c\ up into c-- when "a" is followed by a gallows or s/e glyph may have allowed it in a system that otherwise doesn't, or maybe it just looked nicer. 
Also we have æ in Latin.