Even the Holy Soul Points are not quite worth it - unless you are really on your last sprint of getting Shingen/Morgan. You need to consider that you also need to spend for the 2 Souls beforehand, so it comes at quite a cost to get what you want.
Shingen is also not a Soul a Beginner should strife for since she is not that easy to handle. Herc is in most situations better suited and is easy to obtain if you want to work towards typical meta. The Medal Exchange Shop is really not a tool for beginners or even advanced players to use as a catch up tool. For that it is just to expensive. I really see it as an End-Game-Player Shop to further push what you have.

About grabbing the Gacha Tickets as a spending beginner: Hard to say honestly. On one hand I'd say no, they are not. The other hand though tells me maybe yes. Reason why is, they are on a price which justify the thought of getting them. Compare this to Jewels for example. You get a total of 8 tickets which are basically 8 single pulls if you will. 1 Jewels draw is 300, so you would need 2400 Jewels (they cost 1k Medals, so we are at 8k Medals). The tickets are 3k, so you get far more, besides taking SR-Tickets into account.