Small ships aren't for new players? What ship did you start in?
It's bad etiquette to argue using half of someone's statement. The other part was "for giggles" as in, more of a focus on fun. You're not using one for building a new station in any significant way anyway.
As for what ship this beats, given the internal, weapons (including convergence) and the agility and speed of the ship, if I bought a Cobra mkV I would see no need for an Asp Scout (obvs), Asp Explorer, Keelback, T-6, FDS, FAS and Krait Phantom (aside from as an exploration ship) in my fleet. It would do everything I would want of those others.
I started in a Corvette.
You stated small ships were only for new players or for giggles...even if you include "giggles" your statement is still incorrect. Yea, some Cmdrs use a sidewinder and take it into a high CZ for giggles, not denying that. However, some small ships excel at certain tasks more than medium or large ships, Cmdrs don't use them for giggles, they use them because they are the best arrow in the quiver to get a job done. This is like having a conversation with my 7 year old daughter. I'm tapping out.
As for your ships that you now say are obsolete because of the Cmk5...Asp Scout has always been the runt of the litter, there's been better ships since day 1 than the scout. The same can be said for the T-6. AspX and DBX, can see where you're coming from with this. They both have better jump range than the Cmk5 but also they were trumped by other medium ships that made them "obsolete" to a certain point. Same goes for the FDS and FAS, but they still have more firepower than the Cmk5. Phantom, yea, much better for exploration and did make a good missions runner, but again this was trumped by other medium ships.
The one massive plus for a Cmk5 is it's SCO handling, fuel consumption and and SCO top speed, which whoops everything else. SCO travel though isn't the be all and end all of why you wouldn't use another ship.
Back in the day the cost of ships had a big impact on ship progression. It took flippin ages to earn credits, so things like the T-6 had their place as a stepping stone trading ship. This is no longer the case as you can earn enough credits for almost any ship in hours/days rather than weeks/months.
Not sure the Cmk5 would replace my AspX or Phantom, the Corsair and Mandalay replaced those.
There's such a range of ships in ED that people fly what they feel comfortable flying for any given task, but that doesn't take away from the fact that some are just better on paper at some tasks than others.
Same applies to cars in RL, which is why we all don't drive the exact same car.
o7