Gil is kind of in a weird place at the moment.
Equipment is basically free from 1~119. 1~99 you simply need a weapon to keep up with skill-ups.
At 99 you have a few RoE Intermediate quests to get you into 117 gear. A few repeatable Colonization Assignments will net you enough sparks to get into 119 Peacekeepers Coalition armor which is quickly replaced by two days of Domain Invasion for basically amazing defensive gear (lacking unique job benefits, but the defensive stats are solid for a few quick daily dragons). A few more daily dragons will get you from a 117 sparks or a 119 bayld weapon into an entry Escha weapons.
Boom. At that point you can be soloing V2VE or better Ambuscades until you can start picking up Ambuscade pieces. That allows you to supplement your gil through things you can pick up in the Ambuscade Rewards that you can sell and there still is Domain Invasion Wyrm Ash, even though that has tanked pretty hard.
Everything above can be solo and if you've made friends, it can go even faster (at least Ambuscade can; not daily Domain Invasion pts).
The main thing I could see turning sparks in for, at least for entry level players, would be to afford scrolls. Honestly, a lot of them are either skippable, farmable, or cheap at a NPC shop if you look. Obscure things like Raise II may be passed over by new players until they begin to learn better farming methods, but I really simply don't know how many "new" players this game is attracting.
Sadly the market is all sorts of *** up at the moment because of 3 major factors (and the 4th listed is just a natural problem from unleashing all sorts of campaigns at once, but they do that every May):
1. People that are sitting on all of those duped medals are basically so rich from it that they can afford to buy things are pretty much any price which is making common things go up in price.
2. People that were turning out high quality synth results without losing mats until HQ tier popped are also so rich they can afford to buy things at any price (see above).
3. People with low cost of living or that prioritize this game incorrectly in their lives have used their government stimulus checks to buy gil.
4. The most recent campaign spike flail should just have been called "Make money campaign" due to how many of them were lucrative and some of them (looking at you, voidwatch botters) took little to no effort. Also, the Silver Vouchers getting people Mars orbs to sell every 3 rl days was another "make money campaign".
Since none of the above things are being addressed by SE or they were natural May campaign shenanigans, sparks conversion is just... I mean I guess if they think they saw a lot of sparks bots... it's better than them doing nothing, but there could have been other things looked at or solved a long long time ago pre-Covid19.